The best thing Newgrounds can do about this is to repost all their reviews, just as they were and act as if it never happened. Its like graffiti- you remove it as soon as possible, then people give up bothering to graffiti on your wall after a while.
Sorry to hear about Cannas. Hope he sorts it all out.
Everyone out there- go and change your e-mail password to something really difficult to hack, otherwise if someone uses brute force to hack your e-mail account, they can go to any other account you have, such as Newgrounds, Facebook, anything and get it to send a new password to your e-mail, which the hacker controls- then they control your whole e-life.
Mine now has numbers, letters and other characters in a random order- and it is only written down in THE most obscure place.