A nice value add over what you can already do by just posting a Facebook status update / shooting out a message on Twitter would be to do a time-delayed push of

A nice value add over what you can already do by just posting a Facebook status update / shooting out a message on Twitter would be to do a time-delayed push of the message. If I know I want to go shoot pool tomorrow night, put that on your site, shoot it out over Facebook/Twitter/whatever with a link back to your site, then if I haven't created plans, push out a 'last chance' status update that is closer to the time when I want to go do whatever it is I wanted to do. More generically, I can see value in choosing a strategy to publish information at some future time and not having to do it manually.