Sadly so. Data is the most valuable commodity right now. And some of those sites, like the Lexis/Nexis ones, don't have opt-outs, which is extremely scary.

I've gotten to the point where I check privacy policies before I buy or sign up for anything, I have a throwaway email address without my full name for mailing lists/contests, and I keep a template email in my email folder so that when I buy something/sign up for something on a website, I can quickly send a "please do not share, sell or rent my information to any third parries..." email if necessary.