It's actually an interesting question. For years JWs picked random numbers from the phone book and wrote to them. They would scour the obituaries and send a letter of hope to them as well.
So it is quite possible they can get hold of mobile numbers, and text them a message or send them a link to JWdot org. And they can do that from the comfort of their home. Win win situation as far as they are concerned, especially on a cold winters day.