1. What is Twitter? Twitter is a social networking and micro blogging service that allows you to answer the question, “What are you doing?” by sending short text messages 140 characters in length, called “tweets”, to your friends, or “followers.”
2. Why is Twitter useful for business? Twitter can be used to broadcast your company’s latest news and blog posts, interact with your customers, monitor your company’s reputation, or to enable easy internal collaboration and group communication.

• Broadcast your company’s latest news.
  • Post on Twitter any press or news articles. You can post both pictures and videos via Twitter.
    
• Blog posts.
  • If you have a company blog, tweet each new post to keep your follows informed. Many of the current blog software like WordPress and Typepad have plug ins that will post to Twitter automatically.
    
• Interact with your customers.
  • Many of your customers may wish to tweet ideas and suggestions to your company and you can quickly respond.
    
• Monitor your company’s reputation.
  • Monitor your company name and quickly respond to any negative tweets.
    
• Enable easy internal collaboration and group communication.
  • Twitter is a free way to setup groups for just your employees to collaborate.

Big List of Twitter Tools