A lot of people have been pointing this out to me today. Before today I’d never heard of Flattr.
The payment concept is a lot like Readability’s in that it’s a social micro payment system. The consumers send a flat fee to Flattr and then it gets divided up each month based on who’s sites they visited and chose to “flattr” while there. But you can only “Flattr” someone if they have signed up as a content creator and put a Flattr button on their site.