The very same hackers, Lulzsec, who targeted Sony recently, went after Nintendo's US website too, and posted a configuration file as proof of their evil-doings (though no customer information was compromised.) According to their Twitter account, "we just got a config file and made it clear that we didn't mean any harm. Nintendo had already fixed it anyway. <3 them!" It's not known why they chose to break into Nintendo's site, though maybe it was with one of those "because we can" attitudes. Ambitious sods! [Twitter via WSJ via Kotaku]
If they really don't mean any harm, why not start a legitimate security company that hacks client's systems with the intent of reporting their findings back to the client to help improve security? You know, like Sneakers.
IMHO, the hack and release (if we find anything juicy) methodology simply makes them jerks.