I think it's the modern equivalent of pithy sound bites - it lets people retweet (eg quote) particular parts without any particular effort and allows for infint

I think it's the modern equivalent of pithy sound bites - it lets people retweet (eg quote) particular parts without any particular effort and allows for infintely scalable promotion of the poster. That, and blogs are so last-month maaaaaan. Medium's dead, long live twitter.