I'm hearing a lot of simple, interesting solutions for the spam problem. But Twitter has to be doing things like this, don't they? The main issue is that any

I'm hearing a lot of simple, interesting solutions for the spam problem. But Twitter has to be doing things like this, don't they? The main issue is that any of these methods will hurt marginal users. If you fall into the false-positive pool, you likely don't use Twitter much, and may drop off entirely if your account gets flagged. Twitter can't afford to lose those users, or it will seriously hinder their reach. How valuable is Twitter is it contains a bunch of super users Tweeting at each other? (this all beside the point that any of these methods will kill their "Tweets per Day" and "Total Users" metrics)