Ask HN: Social app without the social part

I'm building an app that has a large social component to it but that's not the point of it. I'm not interested in building the next Facebook, or even an app with all the features of Facebook.

Is there any way I can build my app, let people have their profiles, friends, privacy settings etc all in my database but somehow integrate with MySpace, Bebo, Facebook and let people keep the majority of the social network malarky there?

I'm not entirely sure what I mean, it's much bigger than just a Facebook app and I need to store the information locally (like name, username, password, email etc) but I'd love to tap into people's networks stored elsewhere.

Any ideas? Thanks!