Imagine doing business with a company that compiled information about your political convictions, religious beliefs, health, and family. Now imagine that this company turned around and made such information, along with your name and hometown, freely available to the rest of the world.
If you've purchased something on Amazon.com, you've dealt with just such a company. The culprit is Amazon's Wish List, a tool that lets you build a list of books and other items you might be interested in checking out. Such lists can be viewed by anyone, unless you take an extra step to specify privacy. Indeed, it's possible to use the Wish List information to create databases of apparent liberals, gun owners, teenage girls, and so forth, and even to map them by location.
Read the rest of the Inc. article here. Why don't these companies operate on the assumption that you want privacy unless you specifically indicate otherwise?