Don't be creepy.
I have social network fatigue, so I stick to two simple ones, and occasionally use some others.
Stellar
I got invited into Stellar by a friend. It aggregate favorites from other websites (Twitter, Flickr, Vimeo, YouTube) into one feed which you and others can follow.
Unlike Facebook's new "frictionless sharing", this is truly frictionless in that as soon as you favorite something on a service, it appears on Stellar. It's a nice middle ground between having to explicitly share everything you want to share, and implicitly having everything you do online appear on your profile. It's wonderful.
If you want to know about photos and videos I enjoy online, you might want to follow me there.
Yes, the site is currently in a closed beta. I'm sorry. No, I don't have invites.
I've been on Twitter since January 2007. I've had my account private for a while now. I get a ton of follow requests, and I turn most of them down. My criteria are simple:
- Do you smell of social media marketing/professional SEO douchenozzles?
- Do you seem like you actually care about the topics I'd tweet about?
- Can you spell?
Most people fail two of those.
Other
- I am on Facebook. My profile isn't public. If I actually know you, we probably have a mutual friend and you should be able to see me. If I don't actually know you, don't even bother.
- I am on Google+. I don't really see the point. It really just seems to be a refuge for Google fanboys and Facebook runaways.
- I occasionally post photos on the increasingly dusty Flickr.
- I post code on Github. (Nerd.)
- Music I listen to magically appears on Last.fm.
- Anime I watch is logged on MyAnimeList.
- IIDX scores reside on Solid State Squad, pop'n scores on the pop'n division.
- I tend to post videos on Vimeo. But sometimes, they go on YouTube.