Anyone can sign up. Registration no longer needs an invitation: sign in with any supported provider, pick a username, agree to the terms, and you have a working account. If someone did give you an invitation or promotional code you can still enter it — the code field is simply optional now, and a code issued before this change works exactly as it did. Signing up now includes a quick automated check that you are a person; it normally completes on its own while you fill the form in.

The registration form asks for your username first, pre-filled with the name your account was given automatically, so choosing one is the first thing you do rather than something to find later in settings. If the name you want is already taken, the form says so on the field and nothing else about your account changes — pick another and submit again.

A code you receive after signing up is no longer wasted. Profile settings has a new "Redeem a Code" section: enter an invitation or promotional code there and it upgrades the account you are already using. A code that would not raise your account above where it already is politely declines and stays unused, so you can still give it to someone else or use it later. Following an invitation link while signed in applies the code straight away instead of showing you a registration form you have already filled in.

The "Account Pending" holding page is gone. An account that has not finished registering is taken straight to the registration form instead of being told to email us for an invitation. Until you finish, you can read and explore everything as before — posting, voting and reacting wait for the form, and the controls say so rather than failing when you press them.