Your issue over "stolen" data is a large one in the context of displaying data on the Internet. I have two points for you. First, under standard copyright laws, your information would have to be original work. You would have had to gather the information from primary sources and/or combined information from a variety of published source that you have permission to publish. If your material is from public domain sources, you would have a hard time claiming a copyright.
The second point is people can use limited amounts of copyrighted material; granted they should credit you for the information. The wholesale copying of your material is a different matter. Though the wholesale borrowers are wrong, are you willing to pursue court action for removal from the Internet. You may find this one a hard one to do. The material you post on the Internet is not like a book. You have placed your material where everyone has unrestricted access to your information.
How you proceed in your efforts to restrict the use of your material will depend on how much time, effort, and money you want to spend. A key question to ask yourself is, "Am I using the Internet to share my information or is it out there to make money." Your answer should help determine both your course of action and your attitude about the Internet.