even this is not a sure thing. Thus, especially in biology and medicine, PubMed "associated articles" is a Google Scholar proxy for older papers with no on-line presence. These dynamic web pages are formatted by a Web server when a user requests them and as such cannot be indexed by conventional search engines. Google Books has a pattern of coverage that is in closer accord with traditional encyclopedia content than is the Web, taken as a whole; if it has systemic bias, it is a very different systemic bias from Google Web searches. Quantcast ratings To obtain statistics, visit m, enter url, click "Search." For entities which subscribe to Quantcast 's service, Quantcast declares that their traffic measurements are "verified." This may provide better reliability than Alexa results, as it does not depend on user installation. The user interface and part of the content of the Domesday Project were emulated on a website until 2008. "Microsoft offers cash for Wikipedia edit". 163 Some commentators suggest that Wikipedia may be reliable, but that the reliability of any given article is not clear. Software operations and support See also: MediaWiki The operation of Wikipedia depends on MediaWiki, a custom-made, free and open source wiki software platform written in PHP and built upon the MySQL database system.