I don't think this is due to the limit of 140 characters (even if it doesn't help) but much more due to the audience of fanboys and crow cheered during a fight. There is the same problem on Google+ where there is not 140 characters limit. Any discussions with Linus or any other "celebrity" in it and the comments thread will be full of : "+1", "M. Linus you are so smart, you are my hero", "Well said, ripe him a new on…
There's also the problem of "dot-@ing", where instead of starting a tweet with "@staz", people start it with ".@staz", meaning that the tweet appears in the timeline of everyone who follows you. I rarely see this used in situations that aren't passive aggressive attempts to get followers to pile onto someone you disagree with. Totally ruins any chance of good debate.
(Whoops, accidentally put a dot in front of your name! So sorry.)