Also available on sister sites, see below.

How do you know whether to trust someone online? What if you want to trade with someone you met online, will they rip you off? What if you want to do a wiki with registration, what powers should you grant newbies?

The technical solution has been known in broad outline for a very long time; it's just rarely implemented, in part because those who set up social software usually are going off a bright idea rather than because they've read everything pertinent in the literature.

In short, see trust networks (and alternate phrasings: networks of trust, trust webs, webs of trust, reputation networks, ...). Short of retinal biometric identification, you don't know who people are online. So you establish identities, cryptographically protected. They are vouched for by others of the same type. You decide how much to trust someone (or how much reputation/powers/editing ability to grant them, etc) based on how much they are trusted by someone you trust, etc. The details can get a bit complicated, as with any cryptographic protocol.

One of the policy details that must vary per realm of implementation is how to allow a newbie to enter the relationship network and ascend. But there are already wikis that do this; one common scheme has simple levels people ascend to, basically by being vouched for (apprentice, journeyman, master, etc).

This is the wave of the future, but it's been slow coming. It's rather like OO programming in the 1970s; things often take a very long time to be understood widely enough to be widely used.

Someday it'll be easier, because people will have various established online identities just in the process of growing up, which can be immediately granted probationary status in a new community that recognizes the validity of the process used by the older community that the newbie came from.

Nor will there be just one Orwellian centralized authority. It'll be more like zillions of identities in zillions of communities, unlinked unless you choose to link them.

I'd offer more specific references, but it's been a dozen years since I kept up with the subject, but it was mostly solved even back then. 

-- DougMerritt

Some possibly useful links:

*http://www.firstmonday.org/issues/issue8_8/jordan/index.html
*http://www.advogato.org/trust-metric.html
*http://www.uni-duesseldorf.de/~matzat/conference.htm
*http://www.4k-associates.com/Library/trust

-- JonathanTang
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See WikiNeedsTrustMetrics