I have insider knowledge as I used to work for one of these companies. Depending on the product you purchase the data comes from multiple sources. Also these companies have sophisticated machine learning capabilities to build a profile based on various attributes found in seemingly unrelated pieces of data. So the list consists of credit reporting agencies, public records, your online profiles with public access, cou…
As a person who used to be involved in that industry, do you try to protect your data more? Or is it just a losing battle?
I would suggest anyone wanting to not be exposed to never use your real name or address online if you're not confident they won't share it. Introducing typos or initials or use a nickname for online orders that allow to list billing address separate from shipping address. Billing data typically has a better chance of not being resold, but there are no guarantees, read their TOS if not sure.