In this video, Matt Cutts explains how Google comes up with the snippets and titles seen on search results. Webmasters will learn what goes on behind the scenes and may encounter a few surprises along the way.
Snippets are the blocks of text under the page titles. Google tries its best to make this relevant for each specific query so its contents may change depending upon the keyword. Sometimes they describe what the site is all about and other times they contain an assortment of keyword-related sentences. These may come from the Meta description, the Open Directory Project, or the page content itself.
Titles are also shown on the basis of relevance. For example, untitled pages may be provided with a more descriptive alternative. The same could also happen if all the pages across a site have the same title or if the given title is extremely long and littered with extraneous words. In the case of the latter, the lengthy version can still be used for scoring but it is the shortened version which will be shown to users. This may come as a surprise to webmasters as most are aware that snippets can change but not that titles can be altered as well.
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Snippets and Titles –