Search engine optimization different signals. The leading search engines, Google, Bing, and Yahoo, do not disclose the algorithms they use to rank pages. Some SEO practitioners have studied different approaches to search engine optimization, and have shared their personal opinions. Patents related to search engines can provide information to better understand search engines. In 2005, Google began personalizing search results for each user. Depending on their history of previous searches, Google crafted results for logged in users. In 2007, Google announced a campaign against paid links that transfer PageRank. On June 15, 2009, Google disclosed that they had taken measures to mitigate the
Microsoft Bookshelf the engine would be usable for more ambitious multimedia applications. Thus they integrated a multimedia markup language, full text search, and extensibility using software objects, all of which are commonplace in modern internet browsing. In 1992, Microsoft started selling the Bookshelf engine to third-party developers, marketing the product as Microsoft Multimedia Viewer. The idea was that such a tool would help a burgeoning growth of CD-ROM titles that would spur demand for Windows. Although the engine had multimedia capabilities that would not be matched by Web browsers until the late 1990s, Microsoft Viewer did not enjoy commercial success as a