One of the many burdens of aging must include the ever-expanding accumulation of possessions that seem to defy easy classification for orderly storage and retrieval; you know you have too much stuff when you own something but can't find it, despite concerted efforts to organize items with easy access in mind. And so it has become with information. Today's desktop hard drive is a kind of family basement -- a repository of things ranging from the consistently useful to those which over time grow stale, esoteric, and useless.