Having never used any of them. you're not really in a position to make such a sweeping statement.
Wait... You haven't used them, but I'm not in a position to make that statement...? Or you said I never used them? I don't have an account, doesn't mean I don't know them. Besides, you'd be engaging in ad hominem argument which basically implies you have no counter argument.
Logic not found.
That said...
Cutting your news down to a one liner is ok, since 95% of the time the one liner is accompanied by a tinyurl link to the full story. For a tiny fraction of my day spent reading tweets and making them I'm find it worthwhile, i get to see when the black mesa team release some new beta footage on youtube, or i can get a link to today's relevant course information from a friend or perhaps a link to anything on any topic that someone found interesting. None of which i would otherwise have seen.
You can't compare twitter to a blog really, they're completely different beasts
As I said, news feed is ok. Most of the time when these things don't come with a full press release they can be cut down to "new info - link". That said, a real full post about it is better than 140 chars, about at least 10 to 20 of those will be occupied a link. Even when it is "NEW INFO - link to full info" posts, it seems like a convoluted work around to good'ol rss feed. You get a heads up you got a tweet, which gives you a heads up to the news... All of which could be bypassed by having a heads up directly towards the news.
THAT said, and fully aware I'm quickly becoming confusing, "news feed" tweeters are useful... Most personal ones, however, are not.