it used to be you just signed up. then gavatar was bought by WP (wordpress) and now it requires new signups to have a WP account. So just sign up for an account and ignore that you can have a WP blog.
sucks but what can you do?
I just wish we had the option to also upload our own pictures - it would make it much easier.
that is a todo item on the author of the esoTalk platform.