I am not the first to this idea. Kachingle made a flashy start but fell to pieces first when they got into a crazy vendetta with the NYT and then afterwards when a business-method patent application fell through.
Readability tried but ran into the problem of holding money on trust for websites whose owners can't be identified. They also carried the overhead of running a proxy server. Not worth it for $5 a month.
(I don't include Flattr in this list. I still think that making people think about it is asking too much to make the model work.)
I stumbled on the same basic business model in 2008 and I've been chipping away at it ever since. My honours project at university was based on developing a secure mechanism to track users as they visited different sites. That scheme turned out to be broken. I developed a new tracking scheme, which is currently passing through the digestive system of IP Australia and the USPTO.
I guess the moral is: watch this space.
(Or: give me money, I promise to do smart things with it)