Washington, DC (GenevaLunch) – Citizens of Switzerland and the European Union as well as others who do not need visas to travel to the United States, will nevertheless be required to register online with the US government, starting in 2009. US authorities Wednesday published details (link to US government site has since been deleted, 17.04.2018) noting that the programme begins on a voluntary basis in August. It requires travellers to register no later than 72 hours before a trip begins, but the new system “has, however, been designed to allow for the accommodation of last minute and emergency travelers.”
Related, BBC article on the change