Twitter
What's the difference between email and instant messaging? You might say that instant messaging is, well, more instantaneous than email. In that same vein, twittering is to blogging what instant messaging is to email. Like blogging, tiwttering tells the world what you're up to. Like instant messaging, it does it in a more brief and instant format. You can even use your instant messenger client to update your twitter status by sending a message to a user name twitterim. Twittervision lets you see, graphically, the twitter status updates. So, "What are you doing?"