Search engines must delete data after six months, say watchdogs / outlaw.com, 8 April 2008
http://www.out-law.com//default.aspx?page=9021
"Search engines must delete search logs after six months if they are to comply with data protection laws, according to a committee of EU countries' privacy watchdogs."
Opinion on data protection issues related to search engines / Article 29 Data Protection Working Party, 4 April 2008
PDF - http://www.cbpweb.nl/downloads_int/Opinie%20WP29%20zoekmachines.pdf