How to comment on Unity blog with the username?

Don't know where else to post this.
I always wondered, how do people comment on the blog with its own username and avatar?
I am logged in but it still ask me to put my email and name.

 

We write in our username manually and also the email. The avatar is a tricky one, you need to have an account on gravatar (wordpress.com) and have your desired photo / image set there. Make sure you use the same email address.

 

Oh, I get it.
I thought the system had problems matching my email with the username.