A search engine is an application that searches, stores, and retrieves, data based on some criteria. The three popular search engines are Google, Yahoo, and Bing (formerly msn.com).

The most common search engine is Google.com, but most of its data is directed towards English speaking American users. To correct that issue search engines are available in multiple languages and in various countries throughout the world. For example, if you live in Spain, Google.es would serve your needs better than Google.com

A search engine results page(SERP), is the listing of websites returned by a search engine in response to a keyword search. The results normally include a list of websites with titles, a link to the page, and a short description showing where the searched keywords have matched the content within that website.

SERPs can look differently depending on the search performed. If the search is local, i.e. keyword+city+state, then the SERP that you would see would be composed of the following: The top section would be composed of 3 sponsored listings in the top, 1-10 additional sponsored listings on the far right, followed by 3-10 local business results with the image of a map to the left, followed by 10 organic listings.

If the search is broad i.e. keyword+keyword or simply keyword, then the SERP would be composed of 3 sponsored listings on the top 1-10 additional sponsored listings on the far right, followed by 10 organic results.

Sponsored links are the listings seen in a search engine with an off yellow shaded background. These links are the main source of income for search engines like Google. The average search SERP will result in 3 sponsored listings in the top of the page and up to 11 additional sponsored results in the far right side of the SERP.

Sponsored links are also knowns as pay per click advertising, paid ads, sponsored ads, paid listings, sponsored listings, Adwords listings, and advertised listings.

Local listings results are one of the newest features of SERPs, they consist of a map with 3 or 10 listings of local business owners that can provide a solution to your search. For example, if you look up plastic+surgery+miami the listings in the local business section are of local plastic surgeons.

Top rankings in the local business results can not be purchased, the only way to affect the positioning of your listing(s) is via Search Engine Optimization.

Organic listings are composed of 10 websites relevant to the search that was performed. The organic results vary by keywords; plastic surgeon and plastic surgeons will return different results. Miami SEO and SEO Miami will also return different results.

Google has claimed that their users click (organic) search results more often than advertised results and a particular report (and others going back to 1997) by Pew Internet research shows that many users avoid clicking 'results' that they know to be advertisements.

Crawling is the process by which search engines discovers new and updated pages to be added to their database. Billions of website pages are searched (or "crawled") on a daily basis. Every search engine has a program that they use to crawl websites. Google's program is called googlebot, Yahoo's is called slurp, and Bing's is called msnbot.

Crawling frequency is determined by the search engines, news websites like CNN, get crawled by the minute. Popular websites like blogs are crawled daily, and small business websites can be crawled daily or weekly.

After information is crawled and gathered, search engines organize this data in to a massive index of all the words it sees and their location on each website. It then makes this information readily available for serving it in search results

When a user enters a search, search engines like Google search their index for pages matching the keywords of the search and return the results believed to be most relevant to the user.

Relevancy is the most important piece of the SEO puzzle. Relevancy determines whether or not your website will show up for a search, and in what spot (1-10) your website will show up in the organic listings. In Google, relevancy is determined by a formula with over 200 factors. Some of these factors include content, title tags, descriptions, domain name, website locations (if applicable), and pagerank.

PageRank is the measure of the importance of a page based on the incoming links from other pages. In simple terms, each link to a page on your site from another site adds to your site's PageRank. Links can have a value of 1-10 and can vary depending on the page that its linking to. For example, a link from one law website linking to another law related website will have a higher value than that same link from one law website to a non law related site