Over the years, the guidelines for cache placement have gradually been updated. In years past, certain cache types were experimented with that are now no longer allowed. These include Locationless, Webcam, and Virtual caches. Of these three, Webcam and Virtual caches placed prior to the change in guidelines that prevented their creation were allowed to stay active as long as they were maintained by their owner. These caches are considered grandfathered. All Locationless caches were archived when the guidelines changed.