In the work of CMU-Zoesis, Pfmagic, CyberLife, Extempo, and Origin's Ultima Online we find research groups, and companies, that have built marketable models of virtual friends (and antagonists!). These groups have in common the creation of likeable, attractive, agents which interact with both one another and with users in creating virtual communities. The implementation, and the target ``world'' for each varies greatly however, as we will see.