Actually, Google Web Search is a web search engine owned by Google Inc. Google Search is the most used search engine on the World Wide Web receiving several hundred million queries each day through its various services.
Google's rise to success was in large part due to a patented algorithm called PageRank(PR). Google search all the links that are submitted on the website and cached them, through which the PR is obtained. The exact percentage of the total of web pages that Google indexes is not known, as it is very difficult to accurately calculate. 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, and so on.
When Google was a Stanford research project, it was nicknamed BackRub because the technology checks backlinks to determine a site's importance. 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. The PageRank algorithm instead analyzes human-generated links assuming that web pages linked from many important pages are themselves likely to be important.
