It seems to me possible that, as people see the votes amassing on one side of an election campaign, an extra incentive is added to vote the same way and be on the winning side. Maybe it's a similar psychology to that which causes bubbles in the stock market, though the 'need to win' is a far smaller incentive than making money. For this reason it may be prudent for Interactive Democracy not to show a running total of votes (which is very easy to do with a computerised system).
Is this a trap that the current ePetition systems should avoid too? Or are there 'transparency' advantages to showing the build up of votes?