About TWO years ago I was constantly annoyed by
  the 'secure your account: add your phone number here' 
  banner 

That and an obnoxious, flashing add "It seems you live in Wherever, please klick here if you live in Wherever!" were the actual reason I "deleted" my account about 3 years ago.

With all that shit they pulled during only that period it just proves that it was the right decision to make.

I never looked back.