> Eventually it had to be replaced with an online system that recalculates scores on the fly. This system is a tremendously impressive piece of engineering - it's basically a global, real time peer to peer learning system. There are no masters. The filter is distributed throughout the world and can tolerate the loss of multiple datacenters.
> I don't want to think about how you'd build one of these outside a highly controlled environment, it was enough of a headache even in the proprietary/centralised setting ....