An example is the sale of trademarks by search engines. Right now, it is being done and no search engines have been prosecuted yet. But clearly this is profiting from someone else's trademark, both by the search engines and by anyone that buys keywords of someone else's trademarks.

Another example is reverse engineering. In the United States and many other countries, reverse-engineering is legal as long as it is obtained legitimately, even if the device is protected by trade secrets.