Hi! I've found Facebook to be a good tool to let friends and family know I've updated my blog so yes I think it's helpful. Maybe not immensely helpful, but helpful. Twitter, I find, is good because you can link Twitter and FB together and with one quick tweet it will update both your Twitter feed and your FB feed. I also found that within just a couple of hours on Twitter I had several followers that I didn't even know. After checking a bit, I found that they were following another TMBlogger and that is how they found me. Also, once someone is following you, they can see who you follow and you can see who they follow. Thus everyone finds new followers and interesting people to check out and it just keeps going, so it definitely offers some exposure outside of the friends and family cocoon.
I hope this was helpful. Best of luck!
(snowfly7.com Normal Abnormality)