This is one of the best articles I have read on how to use Twitter for business, so I am sharing the link and an excerpt on my blog.
(Abridged version of article follows, click link above to read the article in its entirety. It is quite useful and has a number of additional tips).
1. Thank you – make sure you include the “@” sign before the Twitter name: For example: “Thanks @indiebusiness for being a terrific guest on our teleseminar on ‘How to Use Video to Grow Your Business.’” Why this works: You are thanking someone, which always helps strengthen a relationship; you are showing others that you know and have a relationship with another person that they might think highly of; and you are subtly promoting something you offered in your business at the same time. In addition, the person you are thanking, if you include the “@” symbol, will be able to tell that you thanked him or her (even if they aren’t on Twitter at the time, they can search on Twitter for any mention of “@” and the Twitter name to see who is talking about them). You can also let that person know through a DM (“Direct Message”) that you mentioned him or her.
2. Useful information (non-promotional) – if you have a way people can save money, or learn something interesting, share it. Why this works: You are helping others, for the purpose of providing information, with no ulterior motive (such as trying to sell your products or services).
3. Kudos – one of my personal favorites. Did you read a great article that featured someone you are following? I do this often, with folks like Guy Kawasaki and Tony Hsieh of Zappos. A typical message: “@zappos – Amazing idea on recruiting in Inc. Magazine.” Why this works: You are offering sincere congratulations – always welcome – and strengthening relationships. You are also showing that you know these folks, which means that others who respect them may follow you.
4. Personal – one of my favorites, but this one is tricky. The key is to connect with others in some way. If you send personal thoughts, make sure they are meaningful. If you send messages like “Going to have a ham sandwich for lunch,” it’s a waste of people’s time. Something like “Getting ready to walk in the Relay for Life for ACS” is a way to potentially connect with others with similar interests. Why this works: You’re showing your human side, and people connect with people.
5. Re-tweets – this means that you are forwarding a message from someone else. The way to do this is to put “RT” before the message. Why this works: This shows that you respect an idea of someone else, which strengthens your bond with that person. It also shows that you know this person, and his/her followers might follow you because of that.
Top Five Types of Twitter Messages to Grow Your Business