@thor
>it would be to gently highlight words in the post you're typing that have been hashtagged frequently, and quietly suggest that you add the hash symbol to them

Thanks, I hate it. That sounds like a dystopian nightmare feature Facebook would implement.

Let me post and talk about what I want, the way that I want to. Stop trying to manipulate how I type out things, stop trying to push what I should say, stop trying to transform me into a mindless content creating algorithm. I'm a human being, not a function of your source code.
That's how I'd respond to this if Facebook or Twitter implemented this.