I’d say 2 related things: one is employing those more empirical patterns— Points, and Levels, ranked and tracked on Leaderboards— in situations where they’re not appropriate. I feel like I’m belaboring the point, but… if your community values fun, and easy-going interactions with each other and helpfulness? Then don’t destroy that fantastic dynamic by comparing members, one to another. Don’t elevate certain members’ status at the expense of everyone else in the community—’cause resentment, factions and gaming are soon to follow.
And related to this is the mistake of rewarding the wrong types of behavior. Specifically, there’s a tendency to want to reward activity (how many times have I contributed, or how frequently) instead of the quality of those contributions. (Do people like this video? Have they watched it? Responded? Linked to it, or embedded it on their blog? Voted for it, or assigned a rating?) Of course, both are important: you want people who are actively engaged and prolific contributors: but you want those contributions to be quality ones: thoughtfully prepared, formatted along community norms, and above all useful or interesting to the community.
A relevant, and recent, example I could cite is Plurk. Now, I absolutely don’t mean to hate on Plurk. It looks like a fine product (it’s kind of a Twitter-like microblogging platform.) But they’re tracking and displaying some very “official-looking” Karma metrics, and even feature a Leaderboard of Interesting Plurkers. My response to this is two-fold: first is… “why”? What community goals does it further? My guess would be that it’s a desire to promote active, high-use Plurkers to the community, that others might find them and opt to follow them as well.
But the prominent Karma score, and a surface appraisal of how it’s generated, might lead one to believe that Plurk is a competition. And, specifically, a competition won by the amount of stuff you do! (Number of Plurks, number of friends, etc.) Most people can see how badly this could end: if someone really wants to make it onto that leaderboard? They’ll probably try mass-friending and spam-blasts first. (Even if Plurk’s system is smart enough to counter this, the overall effect is still negative.) There is a nod to quality—’Quality Plurking’, however that’s defined—but the emphasis appears to be on Activity. And I’d posit that a karma system for an app like this is somewhat extraneous. It kinda smacks of “wouldn’t it be cool if we…”
I also feel compelled to point out that the particular label they use—’Interesting’—is a loaded one: while very complimentary to those who receive it, it’s can also feel derogatory to those who’re left out. There’s a reason why Flickr has only ever applied the descriptor of interestingness to photos, and not the people that take them—and that reason is that the community folks over there have a wonderful awareness of community spirit, and are sensitive to the effects that labels can have.