I believe that those privacy issues are mainly connected to info supplied while registering for a product and some advertising. Even it's been reported that some chain stores are sharing customers' personal info with business partners. It's always good to read website stores' privacy policy.
As suggested by Malwarebytes, we should all limit our email and home address info to known well established businesses (stores, websites etc)
Here is an interesting article on home address security and internet:
If your home address is easily accessible on the web, it can cause serious privacy issues. Use these tips to wipe it off.
www.cnet.com
I seldom register a new product with a manufacturer. In Quebec, the law protects us for manufacturer's warranty, so we don't need to register a product bought in Canada..