In Canada it's only legal if it is prescribed for medical purposes. It's illegal to buy anywhere except at specified places and you basically can't smoke it without a doctors note. That being said - just try and get busted for it. You have to be in the big time before the police start worrying about you here. They can't even keep up with busting the grow-ops they know exist.
From all reports, it appears the operators of Overgrow.com were arrested for some other, yet unknown (likely growing), reasons, and that Overgrow.com was collatoral damage.