Google AdSense Limits Referral Payout to 90 Day Window

" AdSense silently adds a 90-day time limit on AdSense referrals
A thread over at DigitalPoint points out that Google AdSense has quietly added a new term to all AdSense referrals generated by a publisher. They have now instituted a 90-day time limit on that referral, meaning a referred publisher must earn the $100 within the first 90 days, before the referring publisher is eligible to earn that $100 for a completed AdSense referral ... "

http://www.jensense.com/archives/2006/01/adsense_silentl.html