I have one of those sites like milliondollarhomepage.com. Its not a pixel site, but a site where advertisers pay for a link. Suppose I gave money back to the person who spent the most money on ads for a certain period. For example when the site's earnings get up to $1000, I give the person who spent the most on ads, $100. Would this be illegal in any way? Thanks.
Definitely not illegal in any way. Such cash backs are definite in vogue in trade of other merchandise then why not in ad selling. But do check for local laws. I will give an example. In india, you pay service tax on ad revenue recd. if you return part of ads, you wont be able to get refund of such taxes attributable to refunded portion.