In an article in today's online version of The Boston Globe, the reporter discusses several cases where bloggers postings and commentary have been used in court cases long after their words were printed.
Obviously, any time you blog and create commentary in an industry or just on local topics, your words can upset some and can be used against you at any time. As with any other form of digital communication common sense, honesty and a sense of caution will usually keep you out of trouble.
I was told way back when, at the start of my career, to never write down any thing you didn't want your wife to read, or have read back to you by a lawyer or prosecutor in court. Good advice then and better advice now.