Image by Aarthi via Flickr

whack-a-mole

[from the carnival game which involves quickly and repeatedly hitting the heads of mechanical moles with a mallet as they pop up from their holes.]

The practice of repeatedly causing spammers' {throwaway account}s and drop boxes to be terminated.
After sense 1 became established in the mid-1990s the term passed into more generalized use, and now is commonly found in such combinations as whack-a-mole windows; the obnoxious pop-up advertisement windows spawned in flocks when you surf to sites like Angelfire or Lycos.