To my friends on Facebook: I have left Facebook for good. If you are wondering if I un-friended you, I didn't. I just don't exist there any more.
The contacts I had before I left are safely on my hard drive, and should I find or build a replacement that is non-intrusive to me and my friends, you will get an email. You can be sure that, whatever it is I use or build, it will be all about strengthening relationships, not isolating myself from everyone by giving myself false rewards for clicking "like" on people's updates.