If, during the period from July 11, 2004 through March 31, 2008, you were a United States resident who had a Google AdWords account and were charged for clicks on advertisements appearing on parked domains or error pages, you may be entitled to payment under the settlement of a class action lawsuit.
[edited by: bwnbwn at 12:31 pm (utc) on Jun 9, 2017]
Was your error page a true 404 identified or was it a 200?A page is a page. The server response sent depends on many things; UA, IP, type of request, what was requested, etc.
What about the ones this type of activity broke and the business closedRegardless, publishers are governed by the rules just as advertisers are. You tell a publisher they can put ads on a dog and they'll do it, all the while advertisers bid for that spot on the dog.