whack-a-mole
 n.

    [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.]

    1. The practice of repeatedly causing spammers' throwaway accounts and
    drop boxes to be terminated.

    2. 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.