Tomash, I can tell you why *I* vote for tags.
I voted for tags so I could quickly invalidate portions of the cache. Rather than have to track all of the keys associated with my *foo *data, I could tag each key with the foo tag and then do a *tagdelete foo* or something similar and memcached would simple do a delete of the keys that match that value. I would agree that tag retrieval of data would be costly and I would vote against that. I don't believe we should even be able to query a tag and get a list of keys associated with it. But that's just my take on tags. Josef
