A Selective Peering Policy is a reflection of a Selective Peering Inclination - a general willingness to peer, but with some prerequisites.
Peering Policies can be described in these these rough categories:
Definition: An Open Peering Policy is an articulation of an inclination to peer with anyone.
Definition: A Selective Peering Policy is an articulation of an inclination to peer, but with some conditions.
Definition: A Restrictive Peering Policy is an articulation of an inclination not to peer with any more entities.
Definition: A No-Peering Policy is an articulation of an inclination not to peer at all.