Not sure features are a big hurdle... I don't spend much time on hacker news but they have a pretty active community with a pretty bare bone set of features.  I would be curious what their secret sauce is that stimulates so much engagement (other than ycombinator mystique).

SN thoughts: the most immediate risks to stackerz community

k00b

I think its going fantastic. Keep up the fantastic work!

Only serious risk I see is number 3 but I think once you get funding this will help tremendously.