A while ago Nintendo won a lawsuit against retailers that sold and distributed R4 and R4-like devices. In case you didn't know, these are essentially carts which allow consumers to pirate DS games.
Since then, those retailers were sent notices updating them on the situation and were told to immediately stop selling those items in store. Obviously if you look around market places and a few select websites you'll discover that a lot of retailers are ignoring the notice pretty blatantly.
In retaliation, Nintendo has gone to court again to seek out damages incurred from those retailers. In addition, Nintendo have opened up a "snitch" website where people can fill in a form where they enter the URL of specific retailers that are still selling R4 units.
It's good to see Nintendo getting more aggressive on video game pirates, the only thing now is to see how effective it is!