Afvanced Poll w/users?

Hello all, I used a previous version of advanced poll a year ago to conduct an impromptu poll of local opinions on a variety of topics.

Everything worked great, but one drawback was that anyone who knew computers could easily find ways to vote more than once.

However, has there been any investigation into using user accounts with passwords for voting?

Obviously with some sort of email authentication, that way it would be somewhat more reliable...

I searched but couldn't find anything.

Thanks