Not sure where I saw it. I might be wrong to mention it w.r.t. ebooks. (As people have been saying the numbers for individual ebooks are not very impressive).
I tried "file hosting site revenue sharing", and this came up:
http://www.easy-share.com/earn.html
1. We pay you when someone downloads your files. We pay
up to $40 up to $5 per 1000 downloads (for files under 50 megabytes).
2. We count all premium account sales generated from file downloads and pay up to 65% of your total sales.