[closedloop129]

The users punish.

You need a trustworthy core by which you can judge the vote of new users. You can incorporate them until somebody complains about a result that is out of place.

This doesn't have to fully scale. There are many pages without monetary value that won't be manipulated. The tags are an additional signal that can be used where they work. If they don't work, they can be ignored.

But it will scale because there are far more consumers than producers.