Do you have a Customer Satisfaction 'person' / Community Manager in a startup? Or even better, are you one?

How do measure performance of someone like that on your team?

Just like devs, we want to measure by quality, not quantity. I've done a lot of Dev team management, where estimates, sprints and retrospectives work. But with something like customer satisfaction (where the focus is on the satisfaction rather than simply support), how do you know whether someone is performing well?

Any help is appreciated.