It would be a huge change considering Twitter is currently testing a version of the product in which tweets appear the same way they do now, displaying just 140 characters, with some kind of call to action that there is more content you can’t see. Clicking on the tweets would then expand them to reveal more content. The point of this is to keep the same look and feel for your timeline, although this design is not necessarily final, sources say.
Source: Twitter Considering 10,000-Character Tweets
Join my Newsletter and never miss a post, sign up now.