I passed by two different attitudes towards defining trust and reputation on virtual environment:
(1)- having someone accredited to certify my identity, namely a CA;
(2)- having a group of peers to collaboratively define my level of trust.
Both approaches presents some limitations and advantages:
~ pros: (1) easy of instantiation, coordination of standards; (2) democracy of definition, granularity of trust.
~ cons: (1) corporate power; (2) holes of the system.