You're quite right. But pretty much every strategy a search engine uses is susceptible to black hat SEO. I think there's something to be said about having the

You're quite right. But pretty much every strategy a search engine uses is susceptible to black hat SEO. I think there's something to be said about having the system use how others are reacting to your comments rather than just what your content is and who links to it. Yes, you could farm out Delicious accounts and have them bookmark your site, but from a SE perspective it's easier to remedy this problem (Delicious requiring captchas periodically, looking for accounts which have an uncanny amount of similar bookmarks in a span of time, etc) than it is to come up with strange rules about content that the black hat is free to change. Judging by the votes, apparently it is more valuable to point out why a certain idea might not work, even if all of the alternatives have the same problem, than it is to suggest something with exciting possibilities. Nothing against you, personally -- your comment is quite right and I agree gaming is a major concern.