Other people should know that you are using an insulin pump, but many new users are confused about who to tell ...
Certainly anyone who asks is a likely candidate for a conversation about the benefits of your new "friend" (your pump, that is). As a minimum, I recommend telling your co workers and close friends that you are wearing an insulin pump. You may not need to tell them all the details about basal and bolus rates, infusion set differences, tape, temporary basal rates, etc., but let their natural curiosity guide you.
Many users find that wearing a pump allows them to be much more "open" about their diabetes. They find themselves eagerly telling all sorts of different people about their pump. There are stories of pumpers stopping complete strangers to tell them about the "joys of pumping" ;-)