Finding Lists

I recently read an article about companies that sell mailing lists to other companies based on the client’s needs. For example, they could give a mailing list of every male age 16-20 in the area of the midwest for a company that sells video games. I thought that it was such a great idea. These people usually call themselves list brokers, and I have seen some of their lists. They are very well made, and I must say that they are the most comprehensive list of names I have ever seen. It is so neat how they find so many names.