Barry Ritholtz nails the right reasons for blogging, at least as they apply to me personally. There are many times when I let this blog lie dormant, always because of a crowded and/or inconvenient work and meeting schedule. And when it's dormant, I have a constant gnawing feeling as my creative side, such as it is, demands an outlet.
I'm constantly posting things to my Google Buzz feed, because it's so easy, and occasionally to Facebook, but neither is a satisfying substitute for blogging. Now that I've finally got it set up the way I like it (a mere three and a half years after starting) I expect to have a more interactive experience with the occasional friends, random commenters and trolls who stop by.