As a “Twitter Evangelist” I feel like I preach daily about the benefits of Twitter for businesses. And not just Twitter, but all social networks as a rule. Posting online about your business clearly improves your search rankings and can dramatically improve your business “digital footprint” as my friend Brad Wilkerson likes to say.
It can also help you tell your story, promote events, promote your news (PR), recruit good people, etc. The benefits far exceed the negatives in my opinion.