I guess that all depends on the purpose of creating a new account. From the information index:
DO NOT attempt to abuse the foreign aid system with multiple accounts by the same player. Any puppet nation used in the foreign aid system is against the rules. This includes player created nations to send aid to themselves, alliance created puppets to use as a 'bank' for their alliance, etc... Players are asked to help keep the foreign aid system honest and report any violations discovered of these rules in the Report Game Abuse forum immediately. Nations that do cheat will be flagged with a cheat indicator in the All Foreign Aid Offers Across the Globe screen for everyone to see.
If I'm not mistaken there was an instance where a group of noobs tried to use puppets a long time ago, it blew up in their faces.