Simply put, Twitter provides people the ability to have a live, real-time conversation about a topic of interest.
In the case of CLSA, the conversation is about sailing--of course. The benefit of this technology is that it allows anyone who cares to "follow" the conversation to get the most up-to-date information available.
Obviously, it requires people to communicate via "tweets". Short messages sent to the CLSA twitter account. Those who follow CLSA, will get the tweet.
So what?
Here's a simple example. If we're having a race, and conditions are questionable, one could tweet current wind conditions at the lake and anyone interest would be able to make a choice. Do I go or not.
Could be fun, if we participate.