Where’s the accountability for Readability? How do you know if the blogs you read are hooked in with Readabilty? If they aren’t, is the money kept in some sort of interest bearing account as an incentive to signup? Shouldn’t that already be disclosed somewhere?
You don’t have these problems with Flattr. Both Instapaper and Readability could simply scan for the Flattr link during the same time they’re stripping out the other elements. The Flattr link could then be dynamically added to either program if it exists.
I don’t understand why Readabilty, Instapaper, and blogs don’t integrate with micropayment systems like Flattr (http://flattr.com/). Readability’s 30% cut seems like a lot. Why reinvent the micropayment wheel and limit it to just blogs? Other than the payment system there isn’t much functional difference from Instapaper. (disclosure: I’ve only sampled Readability whereas I’ve used Instapaper for a year+)
Moreover all articles a person reads may not be useful. So flattr's idea of "Click if useful" would provide money distribution to worthy.