Any such score, used to deny service to group x based on parameters unrelated to the product itself would simply be discrimination, no?
With that out of the way in small businesses reputation can matter quite a lot. Informally many small businesses know that one guy/shop/service that is not worth having as a client. Regardless of discriminatory issues every client has varying levels of cost associated to doing business with them. So just like Credit Scores are a risk profile for how a person will handle debt. You could envision a subset of social scores as a risk profile on having someone as a business partner/client/provider based on metrics like support cost, likelihood of nickle and diming you, Contract negotiations gone wrong. That sort of thing.
But I'm not sure if anyone still cares about Klout scores. I'm not sure if they ever did, except for fun.