What works on web site comment posting and forums posting doesn’t work so well on Twitter. Christopher Null’s top Twitter etiquette tips on Macworld:
Unlike a Facebook update, a Twitter post can be read by anyone. If you don’t like the implications of this situation, either don’t use the service or set your updates as protected (though some might argue this largely defeats the purpose of Twitter).
Twitter is like adding RSS to microblogging and microreading. The vast majority of Twitter users are readers, not tweeters. It’s an unsustainable model.