Lawyers writing their own blog posts - or just contemplating starting a blog (or blawg) - need to think about who is really going to be reading their posts.
It's been my experience that lawyers tend to think about post topics, to choose vocabulary, and to direct the theme of their blogs, or blawgs, toward their peers -- however unintentional that might be.
When the Reader is Another Lawyer
It's fine to write for other lawyers if your blog is intended to be a lawyer-to-lawyer discussion, usually to show your firm's expertise in an area for referral business (common for appellate attorneys seeking to work with trial lawyers) or because it's a personal journal and you're seeking to share and discuss practice issues with your bretheren (like solos and small firms sharing experiences and advice).
When the Reader is Not Another Lawyer
However, if you want to blog for vertical marketing purposes, then you need to decide on who your targeted readers are - and write for them. Write for your potential client.
1. Use their words, not yours. "Driving drunk," not "driving while intoxicated." "Murder," not "homicide" - you get the idea.
2. Use their industry jargon, not your legalese. If you are dealing with bankers, use financial terms (ROI, etc.). If you are working with contractors, use construction terms (rain delays, change orders, etc.).
Clients want lawyers they perceive understand their situations and speak their language. Blogs, or "blawgs," are grand opportunities for lawyers and law firms to do just that.