I stopped at about the same time as you, but I actually returned a couple of months ago. Without friending anyone. And the reason? I use Facebook as a very simple way to get news about really minor things of importance to me:
+ my climbing gym has some new routes!
+ a new video by K.I.Z, yeah!
+ oh, demonstration against some Nazis demonstrating in my neighbourhood, should definitely go there
+ Someone's looking for a climbing partner next weekend, finally heading out to the rocks again!
So likes have become a poor-man's subscription to an RSS feed and groups have become an easy to follow replacement of forums. The key in these cases is the newsfeed, which is okay for having an overview of important stuff (and without friends is not crowded with inane stuff).
I repeatedly have idle thoughts about a startup idea, combining Facebook with github's business model: Any entity such as users, companies, organizations get a page where they can post arbitrary stuff like on their current facebook profile. Users can subscribe and get an overview on their newsfeed. So far, just like Facebook but without the social crap. Financing is not done through targeted ads but by requiring companies to pay for the service - something like 500 subscribers are free, 1000 - 10 $/months etc. Quite rough around the edges, the idea, but I personally would like such a service. Anyone interested in working on that with me?