Each of us are the best marketers for all the reasons described in these comments. I see a lot of folks expressing a desire to grow a community around their passions, get more users into the tags they frequent, etc.

I've read elsewhere that there is the backbone of an affiliate code within the block chain. I think activating a referral system would be a great help.
My particular area of interest is comics & webcomics. I could see myself building and hosting a site that acted as a custom landing page to this community, explaining all the features and information that would matter most to that particular community. (Most likely in comic book form!) A referral system would give it more priority and I'd even do some ad spending.

On the flip side, the tech is very important. I've mentioned Steemit sparingly to others because it's not quite ready for prime time. We may have bad acquisition at the landing pages & signup process, but all signs point to equally weak retention once people are here. I'm fine with little marketing until the holes are plugged. It'll be interesting seeing new front ends like Busy in the coming months, as well as possible advances in Wordpress integration, etc.

I believe the block chain will be the central database for a plethora of front end sites, so as time goes by the official Steemit.com landing page will diminish in importance.