It seems to me that if you told me that you're running for the House in my district and you'll answer my questions on 8thdistrictva.com or whatever, I would completely believe you're better than the other guy. You might listen to me.
Has anybody tried to do this? To be fair I've barely looked at my representative's web page. But this seems much better than calling or writing a letter. I guess you could email them, but every standard means of communication I just imagine an office full of overcaffeinated interns skimming the message for keywords and picking the closest automatic reply. Most of the time, I'd just want to communicate a simple feeling (eg I don't like this bill) and I'd be okay with them looking at a graph of the poll results.