Interesting regarding the concept of RSS feeds. I recently started using Google Reader heavily instead of the destination blogs. Maybe they'll have to add the code for it on every post...
I just finished up a post talking about these types of things, citing an article where Metafilter reported >$6K in donations. That's currently an exception, but who says that can't be repeated?
Also, I think the 20% cut is too high.
I wouldn't mind contributing to my favorite blogs this way.