Simon Willison proposes the sharing of whitelists as a way of countering the spam problem. His approach of just dumping out the whitelist is a nice, simple implementation, but it has scalability problems as the whitelist grows larger.
By coincidence I wrote the other day a draft of a very simple Group Membership Protocol which lists as one of its use-cases whitelisting. While it solves Simon's scalability problem, it creates another one: it's simply not feasible to query a large number of groups when accepting a blog comment or forum post, as the overhead of doing more than a few queries would be enormous. So how can social networking be deployed in a manner that does scale?( Collapse )