[swarnie_]

I'm not sure the historical data still exists but would this be around the time of organised market manipulation? The spiking gold rings 500% then dumping just before you told everyone else to springs to mind.

[omegaham]

Yeah, it was when the Grand Exchange locked in market rates - you couldn't trade at any price outside 10% of the established price.

At the same time, ClanChat was introduced, allowing enormous groups of strangers to coordinate their activities.