I finished programming a very basic, no frills, phpbb micropayments forum. Here's a screenshot..
$9.35 = the amount of money in my wallet
$0.57 = the amount of money allocated to the post
Here's how it works...
1. A member (Bob) paypals you $10 dollars and you update his wallet (a column in the user table)
2. Bob sees that Sarah has just submitted an awesome post. He clicks the quarter button beneath her post and a quarter is transferred, via ajax, from his wallet to her wallet and the value of her post increases by a quarter.
3. When Sarah wants to cash out, she PMs you the amount she wants and you paypal it to her.
Clearly it would be better if the paypal parts were automated.
As the owner of the forum, you make money when somebody allocates money to their own posts. Theoretically, the income from post "boosting" should vastly exceed any income from banner ads... hence entirely eliminating the need for banner ads. And there's no ad blocker for forum posts.
Post "boosting" only makes sense though when you can sort posts/threads by value. Everybody's going to want to sort by value. And everybody who bothers to post content will want their content to be seen by more, rather than less, people. I haven't added the sorting by value functionality yet because I wanted to first establish how much interest there is in facilitating micropayments for forums.
Here's the demo... Micropayments Forum
If you register, some money will already be in your wallet so you can see how it works.
Would you like to see this micropayments feature turned into a full Extension/MOD? Let me know what your thoughts are.