Twitter is stepping up innovation to enhance the platform’s offer in the face of tough competition. After audio, the social network is now focusing on the written word, announcing the launch of a new option for posting longer texts. So, is Twitter becoming a next-generation blogging tool? Debate and discussion are going strong on Twitter, with many users rushing to the social network to share their opinions, criticisms or ideas — and all in 280 characters. But this limit sometimes proves to be problematic when it comes to complex topics. And while Twitter has popularized the trend for “thread…