Search engine results page
From Seo Wiki - Search Engine Optimization and Programming Languages
A search engine results page (SERP), is the listing of web pages returned by a search engine in response to a keyword query. The results normally include a list of web pages with titles, a link to the page, and a short description showing where the keywords have matched content within the page. A SERP may refer to a single page of links returned, or to the set of all links returned for a search query.
Some search engines cache SERPs for frequent searches and display the cached SERP instead of a live SERP to increase the performance of the search engine. The search engine updates the SERPs periodically to account for new pages, and possibly to modify the rankings of pages in the SERP.
SERP refreshing can take several days or weeks which can occasionally cause results to be inaccurate or out of date, and new sites and pages to be completely absent.
Different types of results
SERPs of major search engines like Google, Yahoo! and Bing may include different types of listings: contextual, algorithmic or organic search listings, as well as sponsored listings, images, maps, definitions, videos or suggested search refinements.
The major search engines visually differentiate specific content types, such as images, news, and blogs. Many content types have specialized SERP templates and visual enhancements on the main search result page.
Advertising (Sponsored listings)
SERPs may contain advertisements. This is how commercial search engines fund their operations. Common examples of these advertisements are displayed on the right hand side of the page as small classified style ads or directly above the main organic search results on the left.
How SERP entries are generated
Major search engines like Google, Yahoo! and Bing primarily use content contained within the Metadata tags of a web page to generate the content that makes up a search snippet. The title tag will be used as the title of the snippet while the contents of the description tag will be used for the description. If these tags are not available, information about the web site on dmoz or content from within the page may be used instead.