I am going to assume it works the same for everyone: When I get textmessages, It doesn't say who is sending the textmessage. It just says its from lj. It would be GREAT if the person couldn't complete the field and send out the textmessage unless they listed their username, or however it really works when you set your options to only recieve comments from registered users and their tag is automatically included with the comment. You could shorten the message length a little and just put their tag at the end of the message. But then I have no idea how any of this works; I'm just a slightly frustrated user getting anonymous posts (text messages) from people constantly.