[hunter2_]

To the best of my understanding, the service only gives out your phone number to people you message (the recipient needs some way to message you back, after all), and the service does not receive nor leak your contact list.

Source: TFA

[em-bee]

i don't want to share my phonenumber with everyone that i communicate with.

my main concern is that i want to be able to block contacts if needed and i can't effectively do that if they have my number