There is a great discussion on pubrants from Friday on who reads a writer's blog. She says editors read your blog - if they might be interested in buying a project from you. They don't randomly cruise blogs, but they will look if they have an interest in you. So make sure your blog isn't filled with errors in spelling and grammar.
A disturbing note - they sometimes look to see if you photograph well! So if you start a blog, be careful what pictures of yourself you include.
I like what one of the comments said though - if you don't like to blog, it will probably show. So if you find a topic you like to blog about, go for it. Otherwise I recommend a basic website that just has your bio, clips, and basic contact information. That at least shows you have a bit of tech savy they can work with.