Privacy concern: Services requiring a phone number for signing up

Question

Whenever a service requires an e-mail address for creating an account, I feel mildly uncomfortable, but I can easily eliminate my privacy concerns by setting up a new e-mail address that forwards mail to my regular one. However, a growing number of services have started requiring a phone number for signing up recently, and I really don't feel comfortable sharing my phone number with them.

Is there a way to work around this unjustified (at least in my opinion) information greed of services? I know that if I were in the US, I could set up a virtual phone number using Google Voice, but I am not aware of similar well-known services for European users. Of course one can find smaller virtual phone number services by doing a web search, but signing up for an arbitrary unknown virtual phone number service seems just as bad (maybe even worse) than giving my real phone number to a well-known service that requires it.

Answer 1

As always, it depends on your threat model. What kinds of privacy intrusions are you trying to protect from, and by whom? It is true that because most people only have one phone number (and one email address), those are used as unique identifiers to aggregate seemingly disparate dossiers of your online and offline profiles, devices, locations, and behaviors. So having multiple identifiers that you use in some systematic way can be useful to reduce this kind of routine commercial (and political, etc.) tracking.

I'm not familiar with specific tools for European users, but having a spare phone number (or multiple) can be achieved by getting one or more virtual phone numbers (assuming you don't have to disclose much personal information to get them), or by getting as cheap a SIM as you can (if it's billed by usage and you only use it for some set of online accounts, you presumably would only be getting a few SMS or data notifications on it). But definitely do avoid sketchy companies, probably not worth the risk.

You may be able to set up VoIP numbers using a service like the 3rd option here, they appear to support EU customers: https://source.opennews.org/articles/shields-using-signal-without-your-phone-number/