To me, the Karma thing isn't bad in itself, it may just be the way it is
a) named
and
b) tallied.
We have a similar gimmik enabled in our chapter's forum, there by default it is called "Reputation" and any positive or negative votes are reflected in percentages. However, I can only increase/decrease the reputation of another member ONCE.
Example: I give a "+" vote to Simpte because I believe he always gives solid advice. Now, if he suddenly goes on a binge-drinking spree and starts giving nothing bogus info, I can change my mind and void my vote with a "-". (Once he signs up with AA and is back to his old self, I can vote "+" again.

) I cannot however, give him multiple positve/negative votes. To me that makes the system a bit more 'fair" and accrdingly to a members overall reputation.
Maybe Mark can tweak this one here to fit along those lines? ... Just food for thought though.