I do use Facebook but I don't put a lot of personal information there. I don't store a lot of photos, I don't check in, and don't do anything much at all but share the occasional story, and like and comment on the occasional post or link. That's more than I do on LinkedIn though. Mostly because I can't find anything else to do on LinkedIn. Likewise Pinterest.
Google+ I use because Google's bundled Hangouts there and that's our office video conferencing tool and what we use for our podcasts. Otherwise, I share the occasional story there too, and the occasional +1 or comment, and I keep up with my Google- and Android-invested friends. Like LinkedIn, however, I'm hard pressed to find anything else much to do there. And... that's about it. Seriously this time. Kinda.