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
History of Microsoft strengthen its position on the search engine market vis-à-vis Google. The company rejected the offer, saying that it undervalued the company. In response, Microsoft withdrew its offer. In 2009, the opening show of the Consumer Electronics Show (CES) was hosted by Steve Ballmer for the first time. In past years, it has been hosted by Bill Gates. During the show, Ballmer announced the first public Beta Test of Windows 7 for partners and developers on January 8, but also for the general public two days later. On June 26, 2009, Microsoft started taking pre-orders at a discounted price for Windows