Gatekeeper, n. - used in sales vernacular to refer to a person who has influence over a decision making process; specifically a person who manages or constrains the flow of knowledge, information, or access to a person.
A group in my company wants to do something, but it is for an area which they have no decision making authority. That authority rests in my group.
So I have been watching this outside group go to various people in my organization, trying to convince VPs, executive VPs, and senior VPs to do this favor for them. And each one of these VPs keep sending the request over to the same person: me. Why? Because I happen to be an expert in the field in question, plus the decision effects what I do. I am the logical person to send the request to.
So I sort of sit on the decision, waiting for someone from the other group to come try to convince ME about what they are trying to do. And I wait. And wait. And I watch them go to yet another VP and do their pitch. Which eventually gets sent down to me.
This other group knows that I should be in the decision making process, but because they think my title isn't high enough, or because they know I see some ethical problems with what they are trying to do, they keep trying to go over me or ignore me altogether. But I still hold significant sway over what happens. Maybe not veto power, but I could certainly make the thing much easier to get done, or nearly impossible to do. And what I would require would only be enough to make my ethical concern go away. But that might be part of the problem since, quite frankly, someone in the other group is set up to personally benefit to what they are proposing. Which is probably why they are being instructed to push so hard for it.
So I just sit on the request, hinting at my superiors about the ethical issue, which makes them want to delegate the issue to me even more.