Glossary

Algorithm: A series of mathematical programs used by the search engines to determine the rank of search results for a given keyword query. Web search algorithms typically take 100-200+ variables, or "signals", into consideration when calculating rank.
Bot: See Crawler.
Content Network: Web sites that have agreed to display contextually-targeted ads next to their content in exchange for a commission.
Cost-Per-Acquisition: See Cost-Per-Conversion.
CPC: Cost-Per-Click: The price an advertiser is willing to pay each time a visitor clicks on their PPC ad on another site. Ranges from a few pennies up to $50 or more, depending on the level of competition for a specific keyword.
CPC: Cost-Per-Conversion: A measure of efficiency for an advertiser that can be used to compare the ROI of various marketing efforts. For PPC ads, the Cost-Per-Conversion formula is:

(Cost-Per-Click * Number of Clicks)
Number of Conversions
Crawler: An automated program that scours the internet, following text links and downloading all of the content on every page it finds into a search engine's index. Crawlers are basically stripped-down browsers that don't accept cookies, fill out forms or "read" Javascript or Flash files.
Duplicate Content: Multiple versions of the same content that exist on different pages. Search engines are not always able to distinguish the originating source of content, so multiple copies could detract from the original source's rankings. Some common examples include content that is syndicated to other sites, spammers that "scrape" content and re-post it elsewhere, or multiple pages for the same blog post (blog home page, post permalink page, etc).
Googlebot: Google's name for its crawler.
Index: A search engine's database of web pages found by the crawler.
Keyword: A word or phrase entered into a search engine.
Landing Page: A page that is designed specifically to capture visitors from an ad or other targeted means and convince them to take a specific action. For many visitors, a landing page is just as important or more important than a homepage because it is their first exposure to a new site.
Local Search Engine Marketing: Improving the visibility within search engines for a business or product within a specific geographic area. Local Search tactics can include organic SEO, PPC Advertising, Social Media Marketing or a combination of online and offline efforts.
Natural Search Results: See Organic Search Results.
Organic Search Results: Results returned by a search engine ranked in order of relevance to the searcher's keyword query.
Pay-Per-Click (PPC) Advertising: Purchasing ads from a search engine in an keyword auction system to be displayed next to relevant search results or adjacent to contextually relevant content within a content network. The advertiser only pays when a visitor clicks the ad and arrives at the advertiser's site. PPC ads are typically text links, although many forms of online ads can be purchased on a PPC model.
Rank/Ranking: The position of a web site's listing in the organic search results. Usually expressed in numeric terms. For example: www.bestbuy.com ranks #1 for searches for "Best Buy".
Redirect: Using a web server to automatically communicate to crawlers and human visitors that a specific page has been moved permanently (301) or temporarily (302) to a new location. 301 redirects are ideal for SEO as most engines will eventually transfer the link equity from the old page to the new one.
Search Engine Marketing (SEM) or Search Engine Marketer: A holistic approach to promoting content, products or services across a wide variety of search engines. SEM is comprised of many disciplines, including Search Engine Optimization, Pay-Per-Click Advertising, Local Search Marketing and Social Media Marketing. Strong Search Engine Marketers are able to integrate with other online and offline efforts by applying basic and advanced marketing principles to search engine strategies.
Search Engine Optimization (SEO): The practice of creating accessible site architectures, authoritative, valuable content and securing inbound links to improve rankings in search engines for a specific set of keyword.
Sitemap: A hierarchical list of web pages that belong to a site. HTML versions are typically part of a site's navigation structure for human use. XML sitemaps are used to communicate a site's structure directly to crawlers.
Social Media Marketing(SMM): Utilizing social networking and user-generated content platforms to promote a product, service or content. Often involves creating and participating in a dialogue with the target audience, rather than forcing an advertisement upon them. SMM can also include creating and promoting viral content that is meant to be shared by users. Many marketers are not comfortable with the lack of control over social media but when approached properly, social networks can be extremely effective channels for building product evangelism, reputation management or corporate branding.
Spider: See Crawler.
Sponsored Search Results: Pay-Per-Click Ads purchased by advertisers to be placed on relevant search results pages. Typically found at the top and/or along the right side of a search results page and disclosed as "Sponsored Results".