It is not prohibited by Google Adsense or YPN terms and conditions.
Ad revenue sharing programs work in that the users register themselves with Google Adsense or YPN (they need a website to do this).
Then they get their Adsense/YPN id and enter it into their profile area.
My
ad revenue sharing mod works in two ways.
When ever a topic is viewed, their is a chance that if the author is participating in the ad revenue sharing program, that their ads will be shown using their ad id. So if any users click ads, they get paid the money directly by Google or YPN. The 'chance' is a probability/percentage which can be set on a PER MEMBERGROUP basis eg 50%. The rest of the time board ads are shown. If board ads are clicked, you get the money.
For non-topic pages a participant is randomly selected to have his/her ads shown. Again this is a 'chance' is customisable. eg 50% chance that a users id will be selected, 50% chance the board ads will be shown.