I just got an invitation to join Ravelry, so I zipped over and did so. Oh, my, there's going to be a lot of keying in information about yarn and projects and patterns. I think I could spend a lot of time there.
Now that I've seen it, I can see why they didn't want to just throw it open to the world all at once. The various databases will benefit, I think, by being built gradually. Even that's not perfect, as I've seen a couple of errors that need correcting.
Anyway, if you've signed up to join, they're clearing the list. However, that list has 4,500 people on it, so it may take them a while.