I think that I shall never see A billboard lovelyas a tree. Perhaps, unless the billboards fall, I'll never see a tree at all. See Kilmer 467:17.

-Nash, (Frederic) Ogden
  Happy Days,'Song of the Open Road'.

  It is essential that broadcasting be surrounded with such safeguards as will prevent the air becoming what might be described as an atmospheric billboard.

-Thornton, Sir Henry
  Address to theAdvertising Clubs of theWorld, Philadelphia, 21 Jun. Quoted in E AustinWeir The Struggle for National Broadcasting in Canada (1965).