You need an invite. You can't get one unless you know someone.
Posted under General
While I can't speak for Albert, it sounds like a decent idea. I dunno about making registration mandatory -- at least leave a view-only anon mode -- but I can see an intermediate level of membership (indicated in the username somehow, so we know who?) that lets us take note of people who are helpful in various ways.
Then yeah, we could consider inviting them. Though it'd be best if there were some sort of PM system so they don't have to post their email addresses in public. Then again, thats what spam accounts are for I guess.