AdSense add Checkout to Referral Products

More AdSense news today - Google are now letting publishers promote their Google Checkout system as a referral product.

Their support page that explains how much publishers can earn from their different products lists ‘Checkout’ as a referral product saying that publishers will earn $1 if the person they refer becomes a buyer and purchases at least $10 (before tax and shipping) within 90 days of sign-up.

Not one of their most lucrative referral products - but I guess on some sites that are shopping based it could convert quite nicely.