It's worth mentioning that there are two classes of this game:

1) I get 47 of my closest friends to mindlessly vote it up in some kind of vote exchange black market.

2) I get one or perhaps two close friends who have read the submission and genuinely like it to vote up so that my submission has a chance to stand on its own merit.

#1 is bad, and makes HN cheap. #2 though is a rational response to a broken system.

I think the right approach to #1 is to algorithmically detect and squash it. The right approach to #2 is to figure out why it's even necessary to do that, and change the system such that it's no longer necessary at all.