Reader Tags?

What do you all think of allowing readers to write tags to stories? This would be an opt-in for authors to allow or not and readers would have to spend buttons to be able to write tags, maybe. I'm just thinking out loud sort of but I found a neat module someone has already written. We'd also need a couple of three "tagerators" to keep the new tags coherent and appropriate. Perhaps authors could moderate tags on their own stories?

Hugs,
Erin