“Since the reveal of the PS4 I have been wondering if it will be able to have two or more profiles logged in at the same time like the Xbox 360 is. We really want to play on a Playstation, but have felt that we had to prioritse the 360 this generation because of this feature. I hope it is not the case this time around.[...]

Good morning Iselin, really glad to hear that you are looking forward to our launch. I have some good news for you – up to four profiles can be signed in on one console on PS4. Thanks for your question, Jim”
Sony say that you can log into multiple accounts at once on the PlayStation 4 | PIXEL ENEMY