I started tracking the advertisers who upload my contact information a few months ago. One day I "hid" all of the pages in that section of the ads settings page

I started tracking the advertisers who upload my contact information a few months ago. One day I "hid" all of the pages in that section of the ads settings page and the next day it showed that over 100 pages had uploaded my contacts. I messaged a selection of the "new" pages (I'm not sure if they were actually new or if the had just re-upped their list). Most of them responded that they were confused as to how my info would end up associated with their pages, since most or all of them are quite a distance from where I live. A couple mentioned that they outsource their marketing to outside groups. My theory is that there may be industry marketing groups that collect contact information for use in social media advertising. One auto dealer worker responded to my question, "how did my name get on a list that your page uploaded?" by saying "I don't know, I just post ads." The ad settings page suggests that usually the uploaded identifying information is a phone number or email address, but the wording is vague enough that it could probably be just about anything. So if you've ever shared your phone number with Facebook (even once, I suspect, even if you've since deleted it) I wouldn't be surprised if they use that to identify you. Similarly, a postal address or even a city might enough to identify you for these purposes. Edit: A quick Google shows a number of groups similar to [1] that sell lists of auto owners. I would be surprised if there were not similar groups for other industries, particularly real estate. [1] https://hedgescompany.com/consumer-automotive-mailing-lists/ https://hedgescompany.com/consumer-automotive-mailing-lists/