It has been some time since I have started to use twitter seriously. Currently I have two accounts, one in English (kenmogi) and one in Japanese (kenichiromogi).
The more I use twitter, the more I seem to like it. And you notice several things that contribute to its excellence along the way, which become apparent only after a period of involvement in this medium.
For one thing, twitter promotes competition in online characters. In some modes of use of the internet, in the case of anonymous entries into the bulletin board system in particular, there was a time when a deterioration in moral was rampant. One could write something truly nasty and/or stupid, and get away with it, in the cowardly haven of anonymity.
Not any more with the twitter. When people write nasty things, and some people (albeit increasingly infrequently) do resort to such follies, the record is there, and it does damage to the perception of the online personality responsible, whether anonymous or in real name.
When you find a nasty comment, you can check the account, and discover that he or she has been making nasty comments on many other things anyway. The attribute of nastiness is then transferred from the specific comment to the personality of the commentator in general. That way, the perceived harm of that comment is diminished.
Twitter is also a medium where different memes "compete" for social resource allocation. People retweet and comment on these tweets which are deemed interesting, often independent of the person who emitted the words. There is effectively a "free market" for interesting ideas and striking observations on twitter. The dynamics of interaction ensures that more web resources are given to the more interesting ideas.
Twitter, in a sense, is similar to the prefrontal cortex of the brain in its functionalities. It allocates attentions and resources of people involved. As an attention allocator, the relative shortness of its message format (140 characters) is crucially important, as it facilitates the rapid evolution of dynamics. Compared to twitter, alternative social media such as SNS (social network service) are often "too heavy" in their dynamics. Unless one is able to select and then magnify a particular meme, one is unable to expand its presence in the web.
Twitter facilitates rapid and efficient resource management by means of the lightness of its being.