If that is the case, then the title is pure link bait; the article wasn't about MTV.com; and the closest to a hack is the social engineering (to whatever degree) used to get the friend to the MTV beach house.
I guess illegally entering mtv.com and doing something with their mail server counts as a hack.
There was nothing illegal as far as entering... he used a mail server for what it was intended for. The impersonation of the MTV legal team is a different story, but it would not constitute a hack in my opinion.