Just want to add one extra thought though:
he or she will run reports against the usage data to find
out whether a given feature is often used. That data can
then be run past the product managers who can help decide
whether it's sensible to just drop the feature.
It's important to be careful here, and it's one of the traps that is very easy to fall into (see Gnome). Just because a feature is only used by 1% of your users doesn't mean it's not important. You might have 100 features only used by 1% of your users each, but if you take out all 100 features, chances are you've taken out at least one feature that every single one of your users depends on, and now your product is a lot worse instead of better.