I have a fledgling blog myself. I find it does three things: 1. Keeps me accountable to continue my story (and to repress every urge I have right now to start editing earlier chapters). 2. Informs others about my writing and other subjects of interest to me. It's more of a personal experiment than anything of great value for others. 3. Unfortunately, it also detracts from what I should be writing: my novel!
Now that I have a smartphone, I update the blog when I have those spare moments where I ordinarily would be doing nothing or playing solitaire on my old phone.
I'm not sure mine helps me stay motivated, but it is definitely an outlet for things I'm thinking about. I think being broke is the best writing motivation
But my blog has slowly become a place where I get to interact with other neo-pro writers and vent writing issues that my friends probably don't want to hear about and wouldn't understand anyway. So it's useful that way
I find it helps me maintain accountability. I also find that it helps me keep track of myself. For example, I have a private section that only I can view that lets me add notes and thoughts whenever I want. I think of a cool new scene while I'm at work, I can make note of it in that section.
Don't know if anyone is still interested in this but here's a Newsletter that has a section dealing with four ways to better blogging. It deals with a class on blogging but the short section gives the four ways. You have to scroll down a bit to find that section.