I have discovered that Jazz.net had redesigned their forum recently and now it looks awfully similar to the Stack Exchange family sites. Is this legal or not? Or maybe they just licensed the design, I just can't find any reference there to SE. PS: their old forum was completely different - like vBulletin or similar. Just plain forum.
They're not copying our CSS or data (and even the latter could be fine given proper attribution), so there's nothing illegal about this.