I used to get a lot of junk mail and wonder where these people got my address from. Later, I found out that they would get them from unscrupulous vendors who actually sold information they had in lists to all these companies who wanted to get a large customer base to send information to. So I had a lot of reservations when a friend who was starting his own company was looking for buy lists services. However, he assured me that the company he was talking to was highly reliable and they had actually been in the direct marketing business for many years already. They had a huge database of clients which included several Fortune 1000 clients and promised a lot of data integrity while helping their clients reach out to customers. It's always best to go with reliable companies.