Google search is a web search engine owned by Google, Inc., and is the most-used search engine on the Web. Google receives several hundred million queries each day through its various services. Google search was originally developed by Larry Page and Sergey Brin in 1997.

Beyond the original word-search capability, Google Search provides more than 22 special features, such as: weather forecasts, time zones, stock quotes, maps, earthquakes, movie showtimes, airports, home listings, sports scores, etc. (see below: Special features]]). There are special features for numbers: prices; money/unit conversions ("10.5 cm in inches"); calculations ( 3*4+sqrt(6)-pi/2 ); package tracking; patents; areas codes; plus rudimentary language translation of displayed pages.

A Google search-results page is ordered by a priority rank called "PageRank" which is kept secret to avoid [[spammers from forcing their pages to the top. Google Search provides many options for customized search (see below: Search options), such as: exclusion ("-xx"), inclusion ("+xx"), alternatives ("xx OR yy"), and wildcard matching ("*").

PageRank

main: PageRank Google's algorithm uses a patented system called PageRank to help rank web pages that match a given search string.Sergey Brin and Lawrence Page. The Anatomy of a Large-Scale Hypertextual Web Search Engine. Stanford University. 1998. The PageRank algorithm computes a recursive score for web pages, based on the weighted sum of the PageRanks of the pages linking to them. The PageRank derives from human-generated links, and is thought to correlate well with human concepts of importance. The exact percentage of the total of web pages that Google indexes is not known, as it is very hard to actually calculate. Previous keyword-based methods of ranking search results, used by many search engines that were once more popular than Google, would rank pages by how often the search terms occurred in the page, or how strongly associated the search terms were within each resulting page. In addition to PageRank, Google also uses other secret criteria for determining the ranking of pages on result lists, reported to be a number over 200.

Search results

Google not only indexes and caches web pages but also takes "snapshots" of other file types, which include PDF, Word documents, Excel spreadsheets, Flash SWF, plain text files, online videos such as YouTube and much more. Except in the case of text and SWF files, the cached version is a conversion to (X)HTML, allowing those without the corresponding viewer application to read the file.

Users can customize the search engine, by setting a default language, using the "SafeSearch" filtering technology and set the number of results shown on each page. Google has been criticized for placing long-term cookies on users' machines to store these preferences, a tactic which also enables them to track a user's search terms and retain the data for more than a year. For any query, up to the first 1000 results can be shown with a maximum of 100 displayed per page.