I don't have enough time to maintain a decent blog. I could maintain a shitty one, but what's the point of that?
Join a community? I barely have enough time for HN as it is!
Stack Overflow? I contribute sometimes, but once again, it comes down to time. If you have the time, I applaud your contributions. As for me, I'll settle for answering maybe one question a month.
New tech? Sure, that's cool. But I really need to get my software to a working state, and that won't happen if I keep changing the technologies. I'd rather wait for a front runner to emerge before joining in.
Twiiter? No thanks. I get enough aggravation from email.
Meetups & conferences? I've gone to a few, but I've found that I can gain a far deeper understanding of a particular language/technology/paradigm through online articles or books.
About the only thing I leave any kind of footprint with is github, because coding is one creative outlet I can't live without.