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.