I have a question, what do companies do with your phone number ? can they trace who you are and what you do ?
One thing I would suspect is they leverage third parties and share your phone number to get back additional known data about you or your interests or other activities which other companies have shared. I think in a way it ends up being a connection point for your data across many places.
How do you combat this sort of thing? Besides periodically changing your phone number, of course
If you might ever need to be reached at the number being shared there's always the route of VoIP products like Google Voice (free), or Twilio or MySudo (not free), where one can create virtual numbers for different use cases. In general it's more secure to share a VoIP number anyway since it isn't vulnerable to the same SIM swapping attacks that cell numbers are. I don't know that it's possible to create a Google Voice account without providing a real cell #. One could probably get around that with a burner phone.
Where there is only a short-term need for a reachable number for SMS verification or communication purposes there are services that provide temporary SMS numbers, like mobilesms.io. Because these numbers are recycled frequently, definitely don't use them to register anything important like a bank account or email address.
They use it to call you up on the weekends to see if you want to come hang out.
One of the more legitimate uses is to have a decent way of identifying humans. Most humans only have a very limited amount of phone numbers (usually exactly one) and even extreme cases can only acquire a rather limited amount of them.
Contrast that to most other identification methods such as email or online accounts where a singular entity can create limitless amounts of them, that's quite a lot better.
Obviously most companies also abuse your phone number for malicious purposes such as tracking, profiling, spam etc.
In France, every company can, and will, sell your phone number to marketing companies. Whenever I switch from one phone carrier to another, I magically get a lot of phone spam in the following week. Then it stops after I have blocked most unknown callers, but it happens every time for me.
But can't they just look in their call logs already? My phone tells me all the info you quoted Google as giving.
