If I understand it correctly, I can use Community Tags as a library filter by using this syntax:
tag:perseus
That's great. However, that specific field is not mentioned in the help file under "Library Filter Fields". Perhaps it should be. Initially not being very familiar with those filters, I sort of had to look for a while before I could figure out how to limit based on Community Tags. Perhaps there are other ways of doing it, but the fact that the syntax listed above works could possibly deserves a quick mention in the help file.

Lew