The quality of a ranking system comes from multiple components.

Only one portion is the algorithm itself.

This is the component that is built.

It has a linear impact on quality.

The other part is the swarm of data the algorithm operates over.

For example, aggregating and distilling insights out of the combined behavior of the whole swarm of users.

This is the part that is grown.

It can have a super-linear impact on quality.

Even very simple algorithms, when distilling the insights of a massive swarm, can have great results.

If you don't harness the intelligence of the swarm in your ranking system, you're cutting out what should be the dominant source of intelligence in your system.