Twitter is a great tool for social networking, but there are some unspoken rules that you should follow if you want it to work properly. Here are four "don'ts" and one "do" for being a good Twitter user.

Don't post too much. If you're posting more than half a dozen Tweets a day you're stretching yourself thin. More than ten Tweets a day and you're either repeating yourself, posting trivia, or pushing your sales message too hard (see below).

Don't mix your messages. Some people start out posting Tweets about their business, but end up telling the world what their dog ate for breakfast. Decide what type of Tweets you're going to post, and then stick to that. If someone started following you because you had good advice about home remodeling, they probably don't care to read Tweets about the menu at your favorite pizza restaurant.

Don't post blatant sales messages. This is a big no no. If all you ever post are Tweets about the latest sale at your store or Web site, you're going to lose followers fast. People don't want those kind of messages crowding their Twitter screen.

Don't abbreviate so much your messages are hard to understand. Twitter has its own language, with abbreviations, symbols and hashtags used to denote certain words and concepts. If you use it too much, however, your Tweets become almost unreadable. Don't make people work hard to decipher your Tweets.

Don't use automated "Thanks for following me" messages. Automated messages are impersonal and even offensive to some people. All you'll do is get a new follower annoyed if you send an automated message to them.

Do offer useful information. Twitter is all about transmitting useful information. You'll gain followers if you provide information they want. Answer questions, post links to useful Web sites, and retweet helpful posts -- that's the way to build a following on Twitter!