The Wall Street Journal recently had an article about the pitfalls that bloggers and Twitterers can fall into if they're not careful. Cisco actually got sued for defamation when an item in its blog accused a couple of lawyers - who were in the process of suing Cisco - of engaging in criminal activity.
Twitter, which is more fleeting and hit-and-run than a blog, seems to be getting people in even more trouble. EBay recently went after a Twitterer who had been following the company's earning reports, conferences, and things like that. EBay forced him to put a disclaimer on his Tweets - and given that they're only 140 characters long, that must have put a damper on his Twittering.
Blog posts move too quickly to get a full compliance review on every item, so bloggers are advised to be careful. Here at Triton, we've been working with advisors long enough to know how to put up meaningful posts that won't run afoul with the authorities.