Jay Deadman has an interesting proposal to create a simple micropayment mechanism for content creators. He proposes adding "payment" to the "rel" attribute. When added to a blog, it would provide an easy way to subscribers to contribute via the tip jar:
Since this is an open protocol, any tool can use this info to connect viewer with the videoblogger to give money. So the link would look like this: Pay Me I created a page at DropCash that will let you donate money to me. rel="payment" is then thing that FireANT or Mefeedia can tell its a Payment button. We were very excited because its so simple. You are just sending someone to a URL...which could be anything: a paypal account, a way to buy your DVD, a place to donate to "save the whales", a page that gives me your P.O.Box to mail a check. It's up to you where you want someone to go to pay you.
Let's see if this goes anywhere. The tag wouldn't provide enough info to iTunes to say, charge a certain amount for a download (although I doubt the amount would be exposed in the RSS feed anyway...or would it?) It is a very simple mechanism; however, sometimes simple = most effective.
Update Based on the comments in Jay's post, it looks like a few vloggers are already trying it out