I've been using twitter for...about two months now. Not exactlt a heavy user, I've made 85 updates in 2 months. When looking at Twitter, one thing that is undeniable is how fast it is growing. So I would say for now it's a success, and as such, it is interesting. But why is it a success? What did they do right? What did they do wrong?
First of all what's good about twitter. When you like someones tweets, you follow them. However, unlike in facebook, somehow its more acceptable not to follow them back. That's a good thing in this case. It allows different types of relationships between people, not just symmetrical friendship.
Next, twitter limits the size of their posts, your tweets. This immediately creates a different medium. Whatever you say on twitter is much less "official", less heavy and serious than your normal blog.
The size limit also forces you to use services like tinyurl, because otherwise a single URL could use up the 140 characters you have per post. The value of URL shortners was recently discussed in many places whether or not they are a good thing. Generally, I think it is a bad thing causing needless redirections, shortening the expected life of your content and fragmenting the "Universal Resource Locator" into different URLs. Just take a peek at my dust paper to see how useful URLs can be.
One thing twitter clearly did right was release an API early. This created a whole eco-system of third-party applications. I believe this still serves to fill the void of missing functionality needed to make the service trully useful.
Which brings us to the next problem. Twitter doesn't scale, at least not in its current level of service. I'm not talking about the computers, the architecture, memcached mysql and what not. No. It doesn't scale for us, the human beings. If you follow around 50 carefully chosen people, you already have to spend way too much time keeping up with them. Many of the posts are going to be duplicates, many of the people you follow will have other "non-interesting" interests and many will hold conversations with people you don't follow which will end up appearing non-sensical on your end. The signal to noise ratio is just too big. Now imagine what happens if you follow 4000 people..
How did Twitter become this popular? I still can't fully understand it. It can't be all PR and hype, right?
And yet...I'm still using it :).