Sinister.ly has been going for the last five years but I revisit this site every week due to it's members always helping with various tech problems and shedding light on some interesting developments.
It started when I wanted to find a decent tech/hacking forum with people who knew what they were talking about and I landed on sinister.ly.
I've learned so much from being on this forum and the people are quite awesome when it comes to answering questions.