[mkjones]

Yeah, we've played with that idea a bit. It doesn't help the sparseness problem (actually makes it worse), and if we took action as a direct result, it would give people the power to DoS content they disagree with.

For sites operating at a smaller scale, this could be a good way to surface content for manual review though.

[peterwwillis]

Could you hire people just to review/flag stuff on a part-time basis, ala Mechanical Turk? Or is the problem just not big enough to warrant the time/money investment?

I imagine that while spam is annoying, it probably doesn't impact your bottom line in a big way.

[RA_Fisher]

Are you using elastic net or other things to handle sparsity? Lots of Bayesian priors?