Mashable has a good list of things not to do (and things to do) with your brand on Twitter.  I realize many of you are just starting your organization’s social media brand, so I hope this is helpful.  This think this item is especially important (many of us break it):

4. Don’t Auto-Tweet

It’s OK to set up tweets to roll out while you’re away from your desk, but think long and hard before you automate an entire feed to stream into your Twitter account. Users can smell a bot from miles away, and the point of Twitter is to be personally engaging more than blatantly promotional. Also, this might go without saying for the tech-savvy marketers among us, but don’t automatically DM new followers; it’s seen as spam. And never DM someone your account doesn’t also follow.