Signing up or Logging in is straight forward. You click on the corresponding button at the top-right of the screen. Now how do I sign/log-out? Clicking my avatar takes me to some profile page. And no, there is no sign-out button/link there. Is this one of those sites where you have to go deleting your cookies to get out?
P.S. And why is there no tag for discussing the usage of this site?