although you need to make a way so that only the constituents get to vote. Senators/Reps are there to represent their state/district, not the overall U.S. population
And since the thing will be online, you don't know whether foreigners are screwing the polls
I covet a congressperson who never acts based on future political ambitions or campaign contributions; it seems like this is a backhanded way to accomplish that goal.
(yes, I'm aware that the demographic of people who are online will skew the results, and that actually I probably DON'T want individual citizens voting on every issue (I don't trust folks to be well informed or intelligent) but this would be a good step forward, imho)