It's a tough call and every one in the eBook biz these days seems to be in the same boat. Just how much time do you want to devote to whizzing around the internet, checking out facebook pages, twitter feeds, promotional opportunities? It's dizzying at times all the stuff out there. Some of it is legitimate and unfortunately, some of it is not. I have several blogs I keep track and follow because they seem to have the most cutting edge news on what's happening in the eBook world. There's just so much quality blogging happening on the internet, so hard to pick and choose.
For hard hitting news I always hit up A Newbies Guide to Publishing there's no BS there. Joe Konrath gives it to you straight.
Another great blog is The Book Designer. Joel Friedlander who has informational articles on self pubbing and highlights other informational self pubbing blogs once a week. Two great resources to start with!