For the Facebook, an update every week or two isn't asking much, and I know PM does work on the site a lot already, it doesn't take anymore than 5-10 mins realistically.
I don't see much point for instagram. If someone wants to show you a pokemon pic, why wouldn't they just use imgur and link it to you?
I myself am going to start making vids soon, but without a proper way of organizing, having one here could go badly wrong. I suggest a community one (I assume most of us have heard about Manchima, the massive gaming channel. The community idea from that seems decent), but make sure we know who and what is going through, by perhaps a rate and approval thread or only certain people being chosen based on how trusted they are / quality of vids ect. we could have vids on how to use the site, where people record themselves commentating about all the little bits of the site and all the features and all that stuff. It could be useful. There are a couple of users (including myself) capable of that. Otherwise, occasional video updates about teh DB, news bites, music and gaming, but try to separate it all if possible.