This WordPress.com account will not interfere with your self-hosted WordPress or other blogging tool if you already run a blog.
WordPress.com is now the account hub for all of our services at Automattic, including VaultPress, Polldaddy, and Akismet.
Polldaddy was acquired by Automattic in 2008, so your data is 100% safe with us — as it really isn't going anywhere.
Once you verify your email with WordPress.com, Polldaddy will ask for your existing account information. Enter it once, and you're done!