I just found an website which offers plugins, that are available on this board for free, for purchase.
Is this allowed by the law? The plugins all are published under the GPL. <- snip ->
That's a known warez forum. Unfortunately there's nothing the MyBB team can do about it.
They ripped a couple of designs that I had done a while back. Not knowing better at the time, I registered and contacted the administration requesting that they remove the content. Not surprisingly, I didn't get a response. I now realize that was slightly foolish after looking around the website a bit more. Unfortunately, OVH more or less ignores abuse reports except in extraordinary scenarios, so I don't think there is a whole lot that could be done without taking it to a court of law.
I don't have a lot of respect for people that feel they should steal content rather than bother compensating the people that have spent many long hours on their work. Most of the theme and plugin authors in the MyBB community are very reasonable with their prices. Authors such as pirata nervo and the audentio team deserve to be compensated for some of the high quality work that they have made available in the community.