Rogue "Tell a Friend" Scripts Inserts Hidden Adsense | Threadwatch.org: "If you're using a third party Javascript on your site, particularly 'tell a friend' from tellafriends.com, then you might want to check out jen's warning that recounts the story of one webmaster discovering that by browsing his site with cookies turned off, this script was inserting it's own Adsense onto his pages.."