This is a parody, but something like this could work:
(1) show a list of bills that are passing Congress / the Senate
(2) for each proposal, show a list of politicians that supports or opposes it
(3) have a way for the user to flag politicians he wants to reward
(4) plus a way for the user to setup a recurring monthly donation, distributed towards the politicians he supports, with a note pointing to your online profile that exposes your interests
What happened to "No taxation without representation"?
This would skew the government even more towards rewarding the rich - increasing the size of the government-as-a-service market is a step in the wrong direction.
What if the total contribution was capped? You could even add that he first $50 of everyone's taxes would be appropriated as that person chooses (Lessig's proposal).
(1) show a list of bills that are passing Congress / the Senate
(2) for each proposal, show a list of politicians that supports or opposes it
(3) have a way for the user to flag politicians he wants to reward
(4) plus a way for the user to setup a recurring monthly donation, distributed towards the politicians he supports, with a note pointing to your online profile that exposes your interests