User acquisition is no doubt one strategic objective that needs to be worked on. I like Seth Godin insight on this; where it's best to implement and test different marketing tactics i.e. put in action to establish what really works and what not. So I'd say open up various ways for people to sign up (and make them visible and clear at steemit homepage); along with how-to-videos for the different proposed ways of signing up. Referral is no doubt one good way, and that's how I got to learn about steemit in fact. Of course a little incentive e.g. couple of SBD or SP would be nice if offered for referring.