The one I recall was Citibank's C2IT. They decided to offer an even larger referral bonus (USD 10 IIRC) so some people ran obvious-sham auctions basically adve

The one I recall was Citibank's C2IT. They decided to offer an even larger referral bonus (USD 10 IIRC) so some people ran obvious-sham auctions basically advertising "we only take this, and here's the convenient referral link for me right here."