[quote author="volta"]Anyone here ever been contacted or threatened by a lawyer after publishing clone info?[/quote]
I have.
BTW, I wrote the article linked at the top of this thread...
The article deals only with the legal aspects of cloning a circuit, not with the moral or ethical implications. The legal limits are fairly easy to define.
Ethics are the rules governing a group, as in how the d-i-y community feels about copying commercial circuits. This can be a nebulous range with some members wanting secrecy and others thinking that everything should be revealed. For example, the d-i-y stompbox group has an ethical stance that schematics of some pedals should not be published because of the wishes of the builder, though there are no legal restrictions for doing this. The group, as a whole, respects the desire of a fellow pedal-builder in this case.
The morals are how you feel bound by your own personal conscience. You may think that all information should be published; "information wants to be free" is the credo often repeated. For others, it is the realization that posting information publically about a commercial device, especially one from a small company, may have a negative impact on that business, reduce sales, and cause lost jobs for their workers. While there may be no legal restriction, a person's conscience may prevent them from copying a circuit for resale or even revealing what is known about it.
As adrianh said, "when you start selling clones it gets real sticky". This is true and the matter of trademarks then becomes an important issue once you are cloning a well known box.
regards, Jack