Twitter is the fastest growing social media site in the world, growing from 2-3 million users in the fall of 2008, to 8 million in February 2009, then to 14 million the following month in March! Projections were that Twitter would hit 50 million users by the end of 2009, but at the 76% month-over-month growth rate for March, Twitter will top that count long before 2009 is done. New competitors entered the space in 2008 but have largely been left in Twitter's wake. Friendfeed is still going strong, and some prefer it's features to Twitter, but most of the new users in this space start with Twitter.

Twitter has evolved from it's simple focus on "what are you doing right now" to become a business tool that should be in any business person's toolkit. I like to think of Twitter as a "virtual Business After Hours," where you're meeting new people, seeing your old friends, catching up on the news, and building your business network.

The Twitter feature that makes it so viral in nature is the "follow" feature. Similar to Facebook's "friends" feature in a way, Twitter users can "follow" each other by simply clicking the follow button next to another Twitter user's name. Don't want strangers following you? Simply make your follow box private, so that you can manually approve any new requests.

The biggest key to building a viral business network is to grow your follower base, i.e., add more people to your netork. CNN is the leading Twitter user with over 800,000 followers at the time of this writing. You can see a list of the top Twitter users here.

So how to grow your follower base? There are several ways to make it happen, here are some of the simplest:

1) Follow people who follow you. It gives you exposure to their Twitter network, and some of those folks may follow you as well.

2) Make tweets that are valuable to your network, and that are on topic to what you do. Let people know you are the expert on the topic. Again, think of being at a chamber of commerce function.

3) Make tweets that let people get to know you personally. Are you a soccer coach? Tweet about the big game coming up tonight.

4) Retweet the posts of other Twitterers. User interfaces like TweetDeck make this easier from a technical standpoint, but you can simply copy/paste the post you like into your status box, then place the word "retweet" at the very front of the post. Many simple post the letters RT.

5) Participate in the Twitter practice of Follow Friday. Each Friday, users tweet the names of their favorite followers, so others can learn about them and add to their own network. Then best way to get involved is to make tweets about your favorite followers (maybe people who replied to your posts this week, or DMd you a nice message.)

Another way to build followers FAST is to learn tactics the experts use. These guys are adding 1000 to 2000 followers a day sometimes, and they have developed some great strategies that are fast and easy to implement.

One expert I particularly like is Rich Bryda, the founder of Brute Force Twitter. I've used Rich's tactics for about half an hour a day, about 15 minutes in the morning and evening, and I consistently add between 700 and 1000 new followers every day.

With Brute Force Twitter, you'll learn some of Rich's tested tactics like:

1) The 5 Minute Feeder Loop

2) The Grocery Store Slotting Technique

3) The time-saving Wall Builder procedure

4) And one of my personal favorites, the Ride The Wave tactic that can add several hundred new followers in only about 90 minutes time.

Now is the time to get started building your following on Twitter. With 14 million users that are projected to grow to 50 million or more, you don't want to let your competitors establish the "beachhead" before you do.