Twitter isn’t raising the 140-character limit. It’s building a wall.
That is, unless they care deeply about the open World Wide Web, in which case they will be free to freak out after all. If I’m right about what’s really going on here, this move will not fundamentally alter how Twitter looks or feels, nor how people use it. Rather, it will change where online content is hosted, who controls it, and who is in a position to monetize it.