Twitter should NOT throw the 140 character limit away, they should continue to enforce it because its their value proposition. There are several sites such as

Twitter should NOT throw the 140 character limit away, they should continue to enforce it because its their value proposition. There are several sites such as Deck.ly (highlighted in the article) for longer tweets and they aren't really popular with mainstream users. Moreover, unlike its considered rivals (Facebook, which I don't consider to be a rival although many tech blogs do after Facebook implemented the status feature) is that Twitter only release changes to its users after a lot of consideration and testing which is another reason as to why they won't throw away their value proposition. Additionally, and potentially the most important fact is that Twitter is a place to communicate with people, discover what new in your world and let them know "what's happening" hence the ability to do so via SMS. By editting the limit etc, they are alienating a core of their users and a CORE which has been the heart of its growth especially during the Iran Elections etc and by editting the limit and adding meta data to it, users in these regions wouldn't have been able to see the tweets properly because everyone on the planet don't own a smartphone. Which would result in a change in using Twitter especially for people in these regions and altering its culture, something which companies work hard to protect and develop.