200 OK
Standard response for successful HTTP requests.

301 Redirect
A response code to state that the URL has moved permanently. This is commonly used when a URL has a new location and will not be appearing again at the old URL.

302 Redirect
A “temporary redirect” is commonly used when a URL has been moved to a different location; but, it should be returning to the original location for future requests.

404 Not Found
The server cannot find the URL requested.

A/B Testing
A/B testing is randomly showing a visitor one version of a page – (A) version or (B) version – and tracking the changes in behavior based on which version they saw. (A) version is normally your existing design and (B) version is the “challenger” with one copy or design element changed.

Absolute URL
The full-path address, such as http://www.domain.com/page1.htm.

Affiliate Marketing
Affiliate marketing is a process of revenue sharing that allows merchants to enhance sales efforts by enlisting other websites as a type of outside sales force.

AJAX
Shorthand for Asynchronous JavaScript and XML. Ajax is a programming language that allows for the updating of specific sections of content on a web page, without completely reloading the page.

Algorithm
A set of rules that a search engine uses to rank listings in response to a query. Search engines guard their algorithms closely, as they are the unique formulas used to determine relevancy.

ALT Text
Also known as alternative text or alt attribute. An HTML tag (ALT tag) used to provide images with a text description in the event images are turned off in a web browser. The images text description is usually visible while “hovering” over the image. This tag is also important for the web access of the visually impaired.

Anchor Text
The clickable text in a hyperlink.

API
Acronym for . A language and message format used by an application program to communicate with the operating system or some other control program 

Backlinks 
All the links pointing at a particular web page. Also called inbound links.

Ban
Also known as Delisting. Refers to a punitive action imposed by a search engine in response their guidelines being broken.

Baseline Metrics 
Metrics which provide a basis for making comparisons of past performance to current performance.

Behavioral Targeting 
The practice of targeting and serving ads to users based on their web-browsing behavior.

Bid 
The maximum amount of money that an advertiser is willing to pay each time a searcher clicks on an ad. Bid prices can vary widely depending on the search engine, competition from other advertisers and keyword popularity.

Blogs 
A truncated form for “web log.” A blog is a website that is frequently updated with commentary or news and is meant to connect with their users. They usually represent the personality of the author, brand or website.

Brand 
Customer or user experience represented by images and ideas, often referring to a symbol (name, logo, symbols, fonts, colors), a slogan and a design scheme. Brand recognition and other reactions are created by the accumulation of experiences with the specific product or service, both from its use, and as influenced by advertising, design and media commentary. Brand is often developed to represent implicit values, ideas and even personality. Source: Wikipedia

Business To Business (B2B)
A business that markets its services or products to other businesses.

Business To Consumer (B2C)
A business that markets its services or products to consumers.

Buying Cycle 
Refers to a multi-step process of a consumer’s path to purchase a product – from awareness to education to preferences and intent to final purchase.

Canonicalization 
The process of setting a desired URL when there are several choices available. This usually occurs on the home page of website when there are multiple options for the URL of page. For example, www.domainname.com, domainname.com, www.domainname.com/index.html

Cascading Style Sheet (CSS)
A file which contains information on layout, font styles, backgrounds, colors, etc.

Click Fraud 
Clicks on Pay-Per-Click advertisements that are motivated by something other than a search for the advertised product or service.

Click Through Rate (CTR)
The percentage of those clicking on a link or advertisement out of the total number who see that link or advertisement. For example, if 10 visit a website and see an ad for BRAND X, but three of the 10 people all choose to click on that ad. That ad then has a 30 percent click-through rate.

Cloaking
The process by which a website presents different versions of a web page to users and search engines.

Content Management Systems (CMS) 
A web application that is used as a method of managing Websites and web content.

Contextual Advertising 
Advertising that is automatically served or placed on a web page based on the page’s content, keywords and phrases. For example, contextual ads for baseball cards would be shown on a page with an article about baseball, not because the user entered “baseball cards” in a search box.

Conversion Rate
Conversion rates are measurements that determine how many of your prospects perform the prescribed or desired action step. For example, if an ad brings in 150 clicks and 6 of the 150 clicks result in a desired conversion, then the conversion rate is 4% (6 / 150 = 0.04). Higher conversion rates generally translate into more successful PPC campaigns with a better ROI.

Cost Of Acquisition (COA)
How much it costs to acquire a conversion (desired action), such as a sale.

Cost Per Acquisition (CPA)
The total cost of an ad campaign divided by the number of conversions

Cost Per Click (CPC)
The amount search engines charge advertisers for every click that sends a searcher to the advertiser’s web site.

Cost Per Thousand (CPM)
A unit of measure typically assigned to the cost of displaying an ad. If an ad appears on a web page 1,000 times and costs $5, then the CPM would be $5. In this instance, every 1,000 times an ad appeared, it would incur a charge of $5.

Dayparting 
The ability to specify different times of day – or day of week – for ad displays, as a way to target searchers more specifically. An option that limits serves of specified ads based on day and time factors.

Deep Linking 
Linking that guides, directs and links a user or a spider to a very specific and relevant product or category web page asides from the home page from search terms and PPC ads.

DHTML
Stands for Dynamic Hypertext Markup Language.

Display URL 
The web page URL that one actually sees in a PPC text ad. Display URL usually appears as the last line in the ad; it may be a simplified path for the longer actual URL, which is not visible.

Distribution Network 
A network of Websites (content publishers, ISPs) or search engines and their partner sites on which paid ads can be distributed. The network receives advertisements from the host search engine, paid for with a CPC or CPM model

Domain
Refers to a specific web site address. For example, http://www.indextree.com.

Doorway Page
Also referred to as Gateway Page, a web page specifically created in order to obtain rankings within the natural listings of a search engine. These pages generally are filled with keywords and are meant to funnel surfers into the main web site. This practice is generally considered an outdated spam tactic. This term is not to be confused with a “landing page.”

Ecommerce
Conducting commercial transactions on the internet where goods, information or services are bought and sold.

Feeds 
A web document that is a shortened or updated (revised content only) version of a web page created for syndication. Usually served at user request, through subscription; also includes ad feeds to shopping engines and paid-inclusion ad models. Ad feeds are usually in Extensible Markup Language (XML) or Rich Site Summary (RSS) format.

Flash
“Flash technology has become a popular method for adding animation and interactivity to web pages; several software products, systems, and devices are able to create or display Flash. Flash is commonly used to create animation, advertisements, various web page components, to integrate video into web pages, and more recently, to develop rich internet applications.” Source: Wikipedia

Frames 
HTML technique that allows two or more pages to display in one browser window. Many search engines had trouble indexing Websites that used frames, generally only seeing the contents of a single frame.

G.U.I 
Stands for “Graphical User Interface.” Means a visual representation of the functional code that allows users to interact with website, electronic devices or software.

Geo-Targeting 
Geo-targeting allows you to specify where your ads will or won’t be shown based on the searcher’s location, enabling more localized and personalized results.

.Htaccess File
A file with one or more configuration directives placed in a web site document directory. The directives apply to that directory and all subdirectories.

Hidden Text
Also known as Invisible text. Text that is visible to the search engines but hidden to a user. It is traditionally accomplished by coloring a block of HTML text the same color as the background color of the page. It is primarily used for the purpose of including extra keywords in the page without distorting the aesthetics of the page.

Impression 
The number of times your ad was served by the search engine or website.

Indexability
Also known as crawlability. Indexability refers to the potential of a web site or its contents to be crawled or “indexed” by a search engine.

Index 
A search engine’s “index” refers to the amount of documents or page found by a search engines crawler on the web.

IP Address 
Abbreviation for Internet Protocol Address, a unique combination of numbers assigned to individual electronic devices or networks that communicate over the Internet. An IP address is an identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the IP address of the destination. The format of an IP address is a 32-bit numeric address, written as four numbers separated by periods. Internet Assigned Numbers Authority (IANA) oversees global IP address allocation.

JavaScript 
A scripting language based on prototype-based programming. It is used on a web site as client-side JavaScript, and also to enable scripting access to objects in other applications.

Key Performance Indicators (KPI)
Metrics used to quantify objectives that reflect the strategic performance of your online marketing campaigns. They provide business and marketing intelligence to assess a measurable objective and the direction in which that objective is headed.

Keyword / Keyword Phrase
A specific word or combination of words that a searcher might type into a search field.

Keyword Density 
The number of times a keyword or keyword phrase is used in the body of a page. This is a percentage value determined by the number of words on the page, as opposed to the number of times the specific keyword appears within it.

Keyword Stuffing 
The act of adding a large amount of keywords into the HTML code or tags of a web page.

Landing Page
Also known as destination page. The web page at which a searcher arrives after clicking on an ad or search result.

Lead Generation 
Websites that generate leads for products or services offered by another company. On a lead generation site, the visitor is unable to make a purchase but will fill out a contact form in order to get more information about the product or service presented. A submitted contact form is considered a lead. It contains personal information about a visitor who has some degree of interest in a product or service.

Link Bait 
This is something on your site that people will notice and link to. By linking to your site, other sites are saying they value the content of your site and that they think other people will be interested in it, too.

Link Popularity 
Link popularity generally refers to the total number of links pointing to any particular URL. There are typically two types of link popularity: Internal and External. Internal link popularity typically refers to the number of links or pages within a web site that link to a specific URL. External link popularity refers to the number of inbound links from external web sites that are pointing to a specific URL.

Meta-Description Tag
This tag is meant to hold the brief description of the web page it is included on. The information contained in this tag is generally the description displayed immediately after the main link on many search engine result pages.

Meta-Keyword Tag 
This is used to show what keywords that page is targeting. This tag is not visible to the users but to the search engines who read the code for that page. This tag is just a guide for the search engines (it does not appear anywhere but the source code for each page).

Multivariate Testing 
A type of testing that varies and tests more than one or two campaign elements at a time to determine the best performing elements and combinations. Multivariate testing can gather significant results on many different components of, for example, alternative PPC ad titles or descriptions in a short period of time. Often it requires special expertise to analyze complex statistical results.

Negative Keywords 
Filtered-out keywords to prevent ad serves on them in order to avoid irrelevant click-through charges on, for example, products that you do not sell, or to refine and narrow the targeting of your Ad Group’s keywords.

NoFollow
NoFollow is an attribute webmasters can place on links that tell search engines not to count the link as a vote or not to send any trust to that site. Search engines will follow the link, yet it will not influence search results. NoFollows can be added to any link with this code: “rel="nofollow"."

Organic Results 
Also known as Natural Results. Listings on search engine result pages that were not paid for; listings for which search engines do not sell space. Sites appear in organic results because a search engine has applied formulas (algorithms) to its search crawler index, combined with editorial decisions and content weighting, that it deems important enough inclusion into the search engines index. 

PageRank (PR)
The Google technology developed at Stanford University for ranking pages and web sites by relevancy.

Pay Per Call
A model of paid advertising similar to Pay Per Click (PPC), except advertisers pay for every phone call that comes to them from a search ad, rather than for every click-through to their web site landing page for the ad.

Pay-Per-Click Advertising
A model of online advertising in which advertisers pay only for each click on their ads that directs searchers to a specified landing page on the advertiser’s web site.

Personas 
These are "people types" or sub-groups that encompass several attributes, such as gender, age, location, salary level, leisure activities, lifestyle characteristics, marital/family status or some kind of definable behavior. Useful profiles for focusing ad messages and offers to targeted segments.

Podcasts 
“A podcast is a media file that is distributed over the internet using syndication feeds, for playback on portable media players and personal computers. Like 'radio,' it can mean both the content and the method of syndication. The latter may also be termed podcasting. The host or author of a podcast is often called a podcaster.” Source: Wikipedia

Quality Score 
Also called Quality Index, a number or indicator assigned by the search engines to paid ads in a hybrid auction that, together with maximum CPC, determines each ad’s rank and SERP position. Quality Scores reflect an ad’s historical CTR, keyword relevance, landing page relevance, and other factors proprietary to each search engine.

Reciprocal Link
Two different sites that link out to each other.

Relative URL
Links to just the file without the full path, for example, “page1.htm”.

Return On Advertising Spending (ROAS)
The profit generated by ad campaign conversions per dollar spent on advertising expenses. Calculated by dividing advertising-driven profit by ad spending.

Return On Investment (ROI)
The amount of money you make on your ads compared to the amount of money you spend on your ads. For example, if you spend $100 on PPC ads and make $150 from those ads, then your ROI would be 50%. (Calculated as: ($150 - $100) / 100 = $50 / 100 = 50%.) The higher your ROI, the more successful your advertising, although some practitioners in search advertising consider ROAS a more useful metric, as it breaks down cost and expenses by conversions per advertising dollar spent.

Rich Media 
Content or advertisements with which users can interact with including but not limited to sound, video, or Flash, and with programming languages such as Java, Javascript, and DHTML.

Robots.Txt 
A text file present in the root directory of a website which is used to direct the activity of search engine crawlers. This file is typically used to tell a crawler which portions of the site should be crawled and which should not be crawled.

RSS 
Acronym for Rich Site Summary or Real Simple Syndication, a family of web feed formats that leverages XML for distributing and sharing headlines and information from other web content (also known as syndication).

Search Engine Marketing (SEM)
A form of internet marketing that seeks to promote websites by increasing their visibility in search engine result pages (SERPs).  SEM methods include: search engine optimization (SEO), paid placement, contextual advertising, digital asset optimization, and paid inclusion. 

Search Engine Optimization (SEO)
This is the process of editing a web site’s content and code in order to improve visibility within the organic or natural results of one or more search engines.

SERP 
Acronym for Search Engine Results Page, the page delivered to a searcher that displays the results of a search query entered into the search field. Displays both paid ad (sponsored) and organic listings in varying positions or rank.

Share Of Voice 
”A brand's (or group of brands') advertising weight, expressed as a percentage of a defined total market or market segment in a given time period. SOV advertising weight is usually defined in terms of expenditure, ratings, pages, poster sites, etc.” Source: Wikipedia

Sitemap
A page that lists all the other pages on that website.

Social Media 
Sites where users actively participate to determine what is popular.

SPAM 
Any search marketing method that a search engine deems to be detrimental to its efforts to deliver relevant, quality search results. Some search engines have written guidelines on their definitions and penalties for SPAM. Examples include doorway landing pages designed primarily to game search engine algorithms rather than meet searcher expectations from the advertiser’s clicked-on ad; keyword stuffing in which search terms that motivated a click-through are heavily and redundantly repeated on a page in place of relevant content; attempts to redirect click-through searchers to irrelevant pages, product offers and services; and landing pages that simply compile additional links on which a searcher must click to get any information. Determining what constitutes SPAM is complicated by the fact that different search engines have different standards, including what is allowable for listings gathered through organic methods versus paid inclusion (referred to as spamdexing), whether the listing is from a commercial or research/academic source, etc. Source: Webmaster World Forums

Spider 
Also known as a bot or crawler, automated program in search engines that gather information about web site by automatically crawling the web. A search spider “reads” page content and coding, and also follows links to other hyperlinked pages on the web pages it crawls. A spider makes copies of the web pages found and stores these in the search engine's index, or database.

Splash Page 
Refers to an entry page or main page of a web site that is interactive or graphically intense. Many splash pages are designed using Flash.

Sponsored Listing 
A term used as a title or column head on SERPs to identify paid advertisers and distinguish between paid and organic listings. Alternate names are Paid Listings or Paid Sponsors.

Submission
The act of submitting a web site to search engines and search directories.

Title Tag 
An HTML tag appearing in the tag of a web page that contains the page title. The page title should be determined by the relevant content and keywords of that specific web page. The content of a title tag for a web page is generally displayed in a search engine result and is visible at the top of the internet browser that you are using.

Trackbacks 
A protocol that allows a blogger to link to posts, often on other blogs, that relate to a selected subject.

Tracking URL 
A specially designed and/or unique URL created to track an action or conversion from paid advertising. The URL can include strings that will show what keyword was used, what match type was triggered, and what search engine delivered the visitor.

Unique Visitor 
Identifies an actual web surfer (as opposed to a crawler) and is tracked by a unique identifiable quality (typically IP address). If a visitor comes to a web site and clicks on 100 links, it is still only counted as one unique visit.

Usability
This term refers to how "user friendly" a web site and its functions are. A site with good usability is a site that makes it easy for visitors to find the information they are looking for or to perform the action they desire.

User Agent 
This is the identity of a web site visitor, spider, browser, etc. The most common user agents are Mozilla and Internet Explorer.

User Generated Content (UGC) 
Refers to content created by users on a third party website.

Value Proposition
“A customer value proposition is the sum total of benefits a customer is promised to receive in return for his or her custom and the associated payment (or other value transfer).“ A customer value proposition is what is promised by a company's marketing and sales efforts, and then fulfilled by its delivery and customer service processes.” Source: Wikipedia

Vertical Website
Websites that focus on a specific industry or sector. These websites much more specific indexes and provide narrower and more focused search results than the general websites, search engines or directories.

Viral Marketing 
Refers to marketing techniques that use pre-existing social networks to produce increases in brand awareness. The awareness increases are the result of self-replicating viral processes, analogous to the spread of pathological and computer viruses. It can often be word-of-mouth delivered and enhanced online; it can also harness the network effect of the internet and can be very useful in reaching a large number of people rapidly. Source: Wikipedia

Website Traffic Analysis 
The process of analyzing traffic to a web site to understand what visitors are searching for and what is driving traffic to a site. 

XML Sitemap
A file that lists URLs for a site along with additional metadata about each URL (when it was last updated, how often it usually changes, and how important it is, relative to other URLs in the site) so that search engines can more intelligently crawl the site. Source: Sitemaps.org

XML 
Stands for “Extensible Markup Language,” a data delivery language.