There's a bit of unfortunate news for those of you under the age of 18 waiting for the official rollout of the new services, though. Major Nelson reports that at launch, Gold members under 18 won't have access to Twitter, Facebook and last.fm features.
That's because right now, there's no mechanism for parents to use the Family Settings options to filter which applications their children should have access to. The current public Update Preview has the same limitation, which has reportedly been a hot topic amongst young Xbox LIVE users.
On the flip side, Major says Microsoft is working on implementing the appropriate Family Settings controls for the new social application integrations. That means under 18 Gold members should sit tight, as the team expects to be able to roll them out within a few weeks after the new Dashboard Update goes live to the public. There's no exact date yet, but barring unforeseen circumstances it shouldn't be an exceedingly long wait.