Kevin O'Keefe of Real Lawyers Have Blogs put together some key elements to have on your blog: Essential law blog pages needed to promote yourself.
I have read too many blogs, for lawyers and others, that do not tell you what the blog is about or who is writing it. Evey blog (including my blogs) wander a bit. You need to pull together a summary of what you are trying to say and where people can find more information about you.
If you are sitting on blogger like me, don't use the standard About link. Create a blog post with the information. Backdate it to keep it out of the feed. Here is my about page: About this Blog and Doug Cornelius. To prove its importance, my tracking numbers show the "About" page to be one of the five most visited posts on this blog.
The one thing Kevin left out is a disclaimer. There is still some uncharted territory with blogs. Bar counsel has barely figured out what to do with Web 1.0. You should label your blog as legal advertising and disclaim any possible attorney-client privilege. I have a disclaimer in About this Blog and Doug Cornelius. Over at the Real Estate Space blog, I was more cautious and put a link to the disclaimer in every post. Since lots of blog content is read through RSS feeds, readers may not see the disclaimer.