[ChuckMcM]

This is something that it would be interesting for these guys to separate out. There are clearly a number of accounts which just submit everything from various 'known to hit' blogs/sites, there are some that submit what ever was a high scoring article a year ago, Etc etc.

What I find amusing is that since they are essentially playing a game "karma scoring for fun" they complain about it when someone else's submission of the same story gets more karma than they got.

That said the use of a mechanism like karma points to drive user engagement and participation is pretty classic. You could ask someone to spend hours day scouring the internet for interesting stories but they would want you to pay them. Offer up karma points to the people who find the cool stories and suddenly they are competing for free to populate the news feed for your site.