I was listening to an interview of Jack Abramoff plugging his new book. Don't know if the book is any good, but one comment that struck me was that, bluntly, campaign donations, all the various perks given to politicians and their staff were bribes. My opinion matches. They're indirect bribes, (mostly) following legal boundaries, but basically bribes for attention if not for outright votes.
What gets a politicians attention is money, and less directly votes - but money can move votes... and people have a poor long-term memory at the voting booth.
I wonder what a open "real-time democracy" Political Action Committee website might look like. Suppose there were tracked tallies of voting intentions, donations, donator "votes" to apply money to issues to be spent on specific campaigns at election time. I imagine you'd want to distribute election targeting data to the PAC voters so they can individually make their resource decisions, maybe to shift their donation to politicians who were most vulnerable in a given district. Sending a politician updates of that summarized data with time series growth might get their attention better than letters. It sucks that we need to bribe your own representatives though...