thanks eberhard
I just meant that if the name is trademarked, then using the word "Arduino" anywhere on the board is protected use that would have to be licensed, even if it's only to say "Arduino compatible" . Form my slim understanding of trademark law, it's ok to put something like "Arduino compatible in the product description, but you need permission first, and it can't usually be within the main title or name of your product. This makes it potentially very hard to attribute in accordance with the CC license. E.g. "Barebones Arduino", "Arduino Prootshield" etc would require trademark licenses/permission. It's an interesting can of worms, isn't it?
D