How to remove your PollDaddy account
Paying members, read: http://support.polldaddy.com/cancel-payment-subscription/
Since PollDaddy works with your WordPress account, you may want to revoke access from WordPress. By the way, also check the WordPress entry on AK: it probably still cannot be removed.
Deleting your account in PollDaddy: simply click the Delete Account button (when logged in, of course). Als see: http://support.polldaddy.com/my-account/
Helpful Trick: Removing online data
Helpful Trick: Remove third-party logins
If you signed up for PollDaddy using a third-party login such as Facebook or Twitter, you probably want to revoke all access from PollDaddy. Click here to find out how.