Embodiments of a decentralized mechanism for detecting the presence of entities in a peer-to-peer network. In one embodiment, using pipes, a peer may uniquely and independently generate an identity for a peer-to-peer network entity. The identity may be used to probe the peer-to-peer network for presence of instances of the corresponding entity on other peers regardless of which peer the identity was generated on and without using a central identity repository or presence system. In one embodiment, net crawling may be used to map identities and resolve the locations of instances of the corresponding entities. An entity may move anywhere on the network, and the decentralized mechanism for detecting entity presence may be used to locate the instance(s) of the entity.