.and if I could mention. There are collectors out there that collect counterstamps and hallmarks (fistfulladirt has a point this stamp being so small). Just a matter of matching the coin with the collector.
I collect
Lincoln Cent counterstamps:
http://goccf.com/t/303507.and at the link I posted a couple of days ago you'll find the more traditional counterstamps some of which are very collectible. You should check out some of ExoGuy's specimens and research.