Some people find it motivating, and motivation is one of the biggest hurdles to overcome. I say give it a try and see if it works for you. Even if you don't have a dedicated following, being public with what you're doing can cause you to worry about your public image.

- Eck

Absolutely, but do it for your own motivation as, based off my own experience, and the low number of comments on most of the journals around these parts, there's a good possibility you'll likely feel like you're talking to yourself week after week, at first:P I've enjoyed mine, and being public about things helps focus my development a little. Though, I have a hard time staying updated when I've taken a step backward or am unable to report much.

I like to use a written journal for idea generation and getting down game concepts, but it doesn't do much for me in terms of motivation. Instead of any sort of "journal," I like to prepare a semi-formal list of deadlines that I put in a very obvious location in my workspace, and I'm able to check things off as I go. Just my personal preference!

I actually do both - I keep a daily written journal for sketching and working out problems, and then I keep a journal here on Gamedev.net to put more polished ideas and progress updates out there. As the others have mentioned, it is motivating to some degree, and in general I find it beneficial to get other people's inputs on your work.

I have also found that the number of comments varies quite a bit, but if you put in the effort to post good content, people will be viewing it for sure.