I've found a lot of non-profit and social work people to learn from there. And have gotten some really great advice on interviewing and job searches there. Of course, it is nichy at times, but it works for me. I've also received faster responses on several job applications by tweeting the organizations that I sent them an application than by e-mailing them the follow-up. That's not to say I don't use it every once in a while for Spurs games and to ramble about the weather and music...I do that as well...but because it's not a closed twitter account I try to keep it professional and not say anything that could offend anyone that happens to google my name.
I haven't really used RSS- for me it's a pain to set up. IMaybe I'll get more into G+ later, but for right now I have the account, but am not using it.