By Dan Levine SAN FRANCISCO (Reuters) – A group of 13 defendants who had been charged in a cyber attack on PayPals website pleaded guilty and admitted to the December 2010 attack over PayPals suspension of WikiLeaks accounts. Following the release of a large amount of classified documents by WikiLeaks, PayPal suspended its accounts so that the anti-secrecy website could no longer receive donations. In retribution, the group Anonymous coordinated and executed denial-of-service attacks against PayPal. EBays PayPal unit is a service that facilitates the electronic transfer of money between parties.