How do you manage having thousands of tags? What is your use case? I quite quickly moved away from them because I couldn't have a strict/normalised system for it. E.g., I would end up with #a, #as, #<synonym of a>, #parent/as, etc. After a while of this, it would either reduce to nothing better than keyword search, or the effort of keeping track of existing tags and the "right" tags would prevent me from tagging at all.