In addition to Assassins Creed IV having exclusive content, it has now been revealed that the highly anticipated Watch Dogs will also have exclusive content on PS4.
http://www.eurogamer.net/articles/2013-04-30-watch-dogs-includes-60-minutes-of-ps3-exclusive-content
http://www.eurogamer.net/articles/2013-04-30-watch-dogs-includes-60-minutes-of-ps3-exclusive-content