Adding this tagline in email signatures is great, although it may seem a bit disjointed on a lot of the content we all might send out. I really think we need a simple tagline like this as an announcement bar on top of the site, or a banner image in the side columns of posts. Tastefully done of course.
As it stands now, I believe if someone lands directly on a steemit article from a google search, as opposed to the front page, there is nothing but the link in the top right corner that simply says "Signup." Your phrase is a lot more explanatory and already contains a hook.
I'd argue that perhaps "users get paid for their content" should be instead "users get paid for their participation." We need to encourage the addition of more participants that may not be content creators in the sense we define them now.