Touched in next post: Simple Social Security II - Legal / Non legal
In most western countries there are laws that try to prevent the information from spreading, but people might break laws and spread (store & copy) it anyway. That is just something you should be aware of but not accept if it happens. Most western countries have also personal security laws that prevent use which you as a user didn't understand it could be used for- and again that you should not accept. If you are unsure on where somebody have gotten the information from, most western countries have laws that state you have a right to know. This is more touched in this post.
So then back to the "beneficial" use, it's called "data mining", using the information to find ways that commercial interest can generate an income. This is in broad terms explained in this video: