i started a thread about this last month when i noticed it..
and contrary to whats been posted, the way this service works they are indeed selling that spot right out from the site owner , and even worse , many times they are selling a directory listing already paid..
example.. i own
www.widgets.com , i buy a directory listing on yahoo for $200, i build my site for 5 years optimizing the keywords "widgets", finally obtaining #1 listing. then yahoo sells my link to wildline who sells it to the highest bidder.. before i got "xxxx" free hits from yahoo , now i pay 15% cut for every hit from yahoo
From the way wildline is setup though , they say they dont sell spots to affiliates , only to owners..
seems rather silly though because any owner buying hits through them is actually buying spots they already own ( or at least thats how i see it , i could be wrong)