Don't worry about people stealing your ideas. If your ideas are any good, you'll have to ram them down people's throats.
Howard Aiken (1900 - 1973)
Some people are very concerned about the possibility of an idea being stolen. They copyright, trademark and patent their assets. This is smart. In fact, it is only natural to put that mark of ownership.
However, the greater question is why they are doing this. Most people who are very focused on this, do it so that they will be able to take their ideas and produce products, services and content that can be offered to the world. If you were to really push them to respond to you, I think you would find that their reason for protecting their work is to be able to offer it to the world in a way that will help sustain their livelyhood and also sustain the quality of the product.
So this discussion of public domain and copywrite isn't as easy as we sometimes make it. We demonize either party without realizing that the Generous Mind can exist in both camps.