I have been thinking about something that I would think to be an interesting business idea, and a way for many to earn money online. And the best thing about it is that it would be completely free and very easy to do, the problem is that it probably isn´t allowed.
My idea is to share Google AdSense profit. Many have probably thought about this before, and I have visited many membership sites where you can add your Google AdSense id and earn money from the site if people click on your ads there. I even think that Squidoo has something like this integrated. This is legal and many are earning money this way.
My idea is a little different. What if the owner of a discussion forum decides to put Google AdSense ads on his or her forums. All members of the forums will get a share of the profits according to how much they benefit, that is how many posts they have on the forums. This will be an incentive for members to be active and keep the discussions alive. A problem would be that this will also be an incentive for spam, and for people to just post without thinking of the contents and if the post is interesting or not. But I bet that a creative forums owner would come up with some sort of rule that would punish the spammers and help people who post great posts with even more money from Google AdSense.
I am not sure about the Google AdSense rules, I don´t think that this is allowed, but it would be great if they would allowe it.