I've been on some mailing lists, but not joined one in a long time. I would prefer not to need lots of proprietary apps for talking to people and email is very standard. I've been known to ask questions on Stack Exchange and sometimes got good answers.
I don't get to go to any technical conferences for work and I probably missed out on stuff. I've been to some Linux ones as well as the HiveFests.
RE: Knowing what you don't know