Myself and 843 other people in Belfast bought a voucher for the local Aquarium which was to expire June 9, 2001. When I received my voucher in the mail, the expiry date had changed to April 9, 2011 without any notice. I asked Groupon about this and they said they had made a mistake and it was supposed to expire April 9, 2011. You may think this was just a simple mistake, but these 'mistakes' are very profitable for Groupon, and here's why. Let's say someone bought the voucher and thought it expired June 9th, they... read full review »