SQLA will probably go live sometime in 2010, possibly before the US midterm elections (what, isn't EVERYONE waiting to see what happens on November 2? :)
Here are some points to consider:
...and maybe there will be a Beta 8, who knows?
Allow me to elaborate: The creator of StackExchange just lost his entire blog because he didn't take responsibility for backing up his own data. SQLA is not my data, it is your data. It's one thing for Jeff Atwood to be careless with his own data, that's his problem. It would be an entirely different matter for me to take the same risks with your data. I don't care how safe the Fog Creek infrastructure is... blah blah blah cloud computing blah blah blah.
Until there is a reasonably convenient and absolutely reliable way for me to back up SQLA content, this site ain't ever going live.
Here's what I really think: The backup problem will go away long before StackExchange goes live, and we'll be able to "pump up the volume" (invite more participation) sometime in January or February.
That will happen before SQLA goes "live"... it will still say "govern yourself accordingly", but it'll be a lot more fun!