When I visit the root domain I shouldn't be greeted with a marketing splash page, you need interesting content in the user's face right away, entice their curiosity and drive the user to explore the site... even as a fellow developer, my first instinct is to abandon the page as soon as I'm greeted with the cliche startup marketing page. Consider the user experience when I visit reddit.com or news.ycombinator.com or any other link aggregation competitor. What you have now is a tech demo, not a platform. Sorry if that's a little harsh, but I mean well! Good luck!
a) seed itself with tons of j referring links. At the end of the day people come for the content not the platform.
b) target moderation groups and convince individual smaller communities to transport themselves wholesale. Go down the dark list and start marketing to each mod team one by one.