Advanced Poll new feature ideas

I'd like to see functionality allowing voting for multiple choices in one poll.

I'd like to see functionality letting users change their vote (ie. change their mind)

You should write a new program.

Yup.

1 - Not to hard to implement.

2 - And short of having them require to have a username and password ow would you achieve this? You could store their IP but IP's change. You could store the entry in a cookie but they may elete the cookie or just not accept it in the first place. Basically unless they have to sign in to use your site this would be impossible.