Recently it has been revealed that the PS Vita will only allow one PSN account per device.
According to a FAQ at a Vita public event, you can only have one account and if you want to change to another account you would have to reset it to factory settings.
Sony’s Brad Douglas, Sony Japan’s Third-Party Relations man tweeted that the PSP also limits a user to one account and the only difference is for the Vita, it needs to be formatted to use another account.
This has definitely been extremely bad news to a lot of people that were heavily anticipating this system. For you that do not know, the PSP do not require a format to factory settings to use another account.