The UNIX multiuser system was the original social network.
$ who bryceo ttyp1 Mar 14 03:32 (vps1.cobryco.com) hugiload ttyp2 Mar 17 13:22 (us02-cip.synopsys.com) pazzed ttyp4 Mar 14 03:39 (proxy1.dcu.ie) jalh ttyqK Mar 18 12:01 (sb.med.harvard.edu)
User profiles too.
$ finger bryceo Login: bryceo Name: Jean-Luc Picard Directory: /home/bryceo Shell: /usr/local/bin/bash Office: U.S.S. Enterprice NCC-1701-D On since Mon Mar 14 03:32 (EDT) on ttyp1, idle 2 days 22:17, from vps1.cobryce.com No Mail. Project: Nothing sepcific at the moment, at least not on devio.us. Plan: Finger?? Really?? Who the HECK uses FINGER anymore? Come to think of it, why do *I* even remember it? And while I'm at it, what's with all the questions?(unix output from devio.us, with usernames changed to protect the innocent)
Something's value can be measured by how much it is shared. Last month I was experimenting with using an IRC Bouncer and setup ZNC. Then I thought hey what if others want a bouncer but dont have a server to run it on? Or just dont want to set one up? So I made a signup page for ZNC on my box that instantly created a ZNC account for whomever wanted it. My approach to sharing limited resources is to start wide open and crank it down if it becomes a problem.
Then another friend wanted to use IRC from work but couldn't because of a networking issue. I gave him a shell account on my server to run screen/irssi. I thought about an account creation screen for anyone who wanted a shell account. There seemed to be an opportunity to ask for something in return for an account.
Zynga and Cityville has an approach to goals in the game, you can pay with social connections or you can pay with credits. Usually people are gifted in one or the other so it satisfies most people. In exchange for a shell account, the system could ask for a Bitcoin payment, or require a minimum connectedness ranking for the tech community that I'm a part of - the Portland tech community.
Building a connectedness rating (if a single vector is even applicable, it might take multiple) is tricky and arbitrary but the Portland tech community has a great catalog of information to help build a rating - epdx.org.