I find the criticisms of Twitter, especially by literate people or authors tiresome. They are so wrapped up in their own cherished conception of what literacy, writing and authorship is, they can't see the creativity and value of Twitter's social sharing mechanism.
At its best, Twitter is like the game of telephone. That is where a child tells the child next to them something, then that child tells the next child, and after going through several children, a slightly different story emerges. I believe this is a _good_ thing. What I loved about "retweeting" when I first discovered it on Twitter, was how it was a editorializer's paradise. Tweets in the process of being retweeted simply begged me to rewrite them, reorganize them, expand or comment on the idea, adding my own ideas and thoughts to the original tweet. Perhaps even shifting it entirely into my own framework. I posted my retweet in the glorious knowledge that someone else might take my words and reformulate them. I welcomed this lateral change.
The social retweeting created a kind of sideways motion as a tweet passed through many hands unlike anything media has ever seen before. It is not commentary, nor sharing, but a process only a social network could produce. It was not an author reacting to another's essay. Or a commentator commenting on an original with an original of their own. It was more like the wiki process only sideways through time and information space. Each person contributed a small effort, made a small change, but the results were not collected together into a single document, but spread out through time and place.
This was something completely unexpected by me (I had worked on a blog system in the late 90s that enforced a limited content length but gave up on it as being impractical...who would want to use it? But combined with social following and sharing, that was something entirely different. The brevity of the post lowered the barrier to participation, but the retweet and the resulting game of telephone was something unexpected). Its a shame the new built-in retweet system discourages this fabric of editorializing. I suppose it was done in the name of efficiency, or perhaps fears about copyright resulting from the game of telephone. It would be a shame to bring such a wonderful experiment to and end out of such absurd fears.
(By the way, this game of "telephone" adds value, not noise to the signal.)