A peer to peer based selection mechanism for admission in a peer group.
"We don't want everyone to join us. It is by invitation only, as when someone seeks to join a closed community, like a co-housing community. There needs to be a mutual acceptance between the applicant and the community they wish to join — otherwise it will be destined for failure.
This is where the principle of vouching becomes important. As was illustrated with Fight Club, the community grows via a process of self-selection where only those who are personally invited by its current members can join. The mafia, to cite a famous secret community, has very strict rules of admission using such vouching rules. linkedin is a quintessential example of an online social network service that extends ones' professional contacts via chains of personally known referrals.
The question for us is how a mutual aid network can use the rhizomatic nature of the web to form new community, translating our virtual community into real community using strategies that guarantee trust and reciprocity through vouching and credentialization. Essentially, we seek to create our own social network service, one specifically designed to create mutual-aid Tongs that would help cement the bonds of new community, foster trust and a spirit of reciprocity, and produce practical results in the real world." (http://inspectorlohmann.blogspot.com/2006/12/building-invisible-comic-community.html)