del.icio.us has just introduced tagging items for others. This is pretty cool, I guess. It could be done before by just asking your friends to use a certain tag when they wanted to share a site with you. This kinda gets away from a true folksonomy: they're telling you how certain tags should be used. I would rather see this happen organically in the community with no help from the admins. Also, this could open the door for spam... and spam isn't what comes to mind when I think of del.icio.us.