Strongly recommending you find some people who're interested in curating and whom you trust to make good decisions. There are many ways to automate and quantify

Strongly recommending you find some people who're interested in curating and whom you trust to make good decisions. There are many ways to automate and quantify such things, but sometimes the uman factor cannot be avoided. Letting people tag things privately, and then contacting the ones who seem to be doing prolific and/or high quality tagging would seem to be an easy selection process.