Now we currently don't have any "official" guidelines, but they did have a few recommendations. High on their list was looking at the University of Florida's social media guidelines (PDF), which really showcase best practices.
Twitter — Best Practices
Writing and Engaging Followers
• Post regularly – Three to four tweets per day. Provide consistent, ongoing and relevant content. Committed, ongoing effort over several months.
• Be retweet friendly — Limit tweet characters so that your message can be rebroadcast or retweeted. This will allow your message to be virally sent out and still refer to your original site.
• Retweet — Retweet relevant material from UF and external sources. It builds a
relationship between other media sources and followers and establishes you as a valuable source of information.
• Acknowledge followers — When possible, a direct message thanking a follower for following your account builds rapport.
• Account Name — Name of profile should reflect name of UF name/unit, not the person updating feed. Use the website and profile description to add further content about your unit and its mission.
• Bio Information — Provide account owner/manager name in your Twitter bio - this provides transparency and accountability. If you use an application like CoTweet to allow for multiple managers, develop a standard of signing tweets so individual manager's contributions can be quantified.
• Following — University Twitter feeds are encouraged to follow the feeds of other University units.
• UF Policies — All produced content must adhere to current UF policy, including (but not limited to) the Acceptable Use Policy. Always remember that as an official UF Twitter account, you are representing the University.
• Registration — Register with Web Administration in order to be added to a list of official Twitter accounts. This will provide a means of gaining followers and will also be an official verification of UF affiliation.
• Avatar — Create a branded avatar that represents both the University and your unit.
• Background — Develop a Twitter background that reflects your University branding and that of your unit.
John Martin from OIT had some guidelines about purpose. He suggested that you consider not only your audience, but also categorize what you want to tweet about - if it doesn't fit into those categories - don't tweet it. His are:
How have you handled school accounts?