gray lady/gray man
What you disgustedly see when viewing a profile or friendship-request for someone who either has cancelled his/her Tagged account or has not uploaded a photo, and so all that's there is a "generic" pale-sliver silhouette of a gal's or guy's head, with no facial-features or other identifying details at all.
I think that a lot of ghosts must be creating profiles on Tagged/hi5, since a lot of them merely have gray lady/gray man images, and the profiles "fade away and disappear" so readily and frequently.