Is there any way that I can find out how many domains a person has, and what they are? If I know the email address associated with them, is there a way of using something like whois to find the addresses?

There's no official service, but DomainTools claims to offer it to customers for a price.

I don't think it would be easy for you to find the info if the domains are private/ (whoisguard) enabled.

there's a way just google it I not going to do research into but its easy I am doing other stuff at the moment. look up domain tools or something like that.

Cyberworld, Google is my friend so if it's doable I'll find it. Thanks for that.

I had seen the paid for service but for the reasons that I want to know I just can't justify the costs that they are asking.

The domain names might belong to the same person but with contact info of his relatives. I assume that might appears quite difficult kind of task

You can use domains tool to know the contact information of the domain. However, you will need to pay some amount for that.

Where? If everyone can get infor he ias needed through automated and paid service what is the idea of privacy protection then?

The only people who can get 100% of the whois info associated with the internet is the authorities. Private regs help cover those who do not wish to be found.

I don't know of anywhere you can randomly find such information.

If you're looking to be sleuthy perhaps you can just e-mail through a proxy from a new random e-mail? If you know one of their websites you can just say how much you liked that one and wondered if they had any others as you'd love to see what else they own? Flattery will get you everywhere...

I have to agree with purple on this one. If you want to be sly about it then try that suggestion. Public domain registries are somewhat easy to search however you most likely will not find information on a private one.