cool and good

It's an interesting idea, though at that rate I would probably think it prudent to redesign the page to not have those ad slots at all and have a "community events" section or similar better catered to the kind of content is coming from said users. Especially when using adblockers is the internet equivalent of seat belts and is thusly taken out by many users anyway.

Don't really have much of a thought. The profit motivation isn't as high or nonexistent, so the chances the banner gets blocked by adblockers are much lower.

that's pretty cool

Great idea, as long as they don't obstruct functionality or target based on tracking profiles like some ads do. I like the idea of using that space for something I might actually care about.