Just because 140 char limit worked for a text media does not guarantee that very short length works for every media. What next, 5 second podcasts? Or should we call them 'shoutouts' rather??

Even with 140 char twitter, unless a very strong opinion by an important person is being conveyed succinctly, most of the (useful) twits exist to give a short opinion on a larger piece linked to by a shortened url. The rest are your standard "I brushed my teeth, I just got of my car etc..." stuff that I leave the usefulness of for YOU to judge.