How do you know when no one working on a software product actually uses the product? Easy: when key functionality is implemented in the most unnatural, cumbersome way that goes against any common sense.
Case in point: Twitter's mobile site. Why would you put the reply button and word count in the most inaccessible place that scrolls away when you start typing? Because you never ever use the product yourself.
Bonus: try replying to a long thread of comments. Yup, you guessed it: the reply button will be at the very top of that long thread.