I find Twitter useful for several reasons:
1. I often get news even before it’s posted on websites, sometimes a day before an editor processes it for general release, and it all downloads to my handheld so it doesn’t need to be connected as it would if I were surfing the Internet. It saves a lot of time to have it all in one place, without visiting dozens of websites every hour to check what's new.
2. Twitter is the most horizontal medium I know. Foreign ministers and celebrities, friends and random seekers can all pick up on what I tweet, and conversations develop with a built-in audience. It’s interest-driven. And Twitter convos have led me to face-to-face dialogue and collaboration, even overseas adventures.
3. It’s a great way to “drive traffic” or otherwise promote ideas and articles by me or others - including my blog posts.
4. Boiling an idea down to just 140 characters is a good exercise. It doesn’t always need to be the whole idea, just enough to get people to open the link or visit the site.
5. Even without the often ambiguous value of “metrics” and analytic data, it’s easy to know when your idea catches on, and why, and in real time.
I generally post differently to Twitter and Facebook. Twitter is the open arena, where ideas can be judged on their own merits. Facebook is for people I actually know, for whom specific ideas are important but secondary to our personal ties and trust. If I post the same items to both, why should someone follow me on both?
Many people seem to follow their followers, and vice versa, I have relatively little overlap between my followers and those I follow. It is a good strategy to follow influential people, so you have access to their perspectives and news firsthand, and sometimes they will follow you back (or at least notice when you re-tweet them).