Twitter was actually not supposed to become something like this, but nowadays more and more blogs start sending updates through it. Due to the 140 character limitation, these updates tend to contain only the headline and a (shortened) link to the original post. A very obvious example is the German A-Blog Spreeblick. Some other users do the same, but not with their own posts, but instead, the tweets link to various sites which are worth sharing.
Otype already claims the death of RSS, but here is my own opinion: why not both? I like using Twitter from my mobile phone, because of its simplicity and its real-time manner. But if I really want to read news, not „brain farts“, I still use an RSS-Reader, even when mobile. With it, I can easily prefetch the feeds at home with WiFi and then read them offline when on the way. This preserves bandwidth and battery, which is not unimportant. And on the desktop, RSS still beats Twitter because you can organize feeds in categories.
So yeah, Twitter is cool for sharing, but it is still not a real syndication alternative.
[Update] Techcrunch also tells us to switch to Twitter and to let RSS die.