If you........post a blog and no one reads it is it still a blog?
If a tree falls over and hits the ground in a forest and no one is around to hear it, does it still make a sound?
The answer to both questions is... yes!
You have to have something in both the subject box and the message box or it won't let you post the blog! If you type a single character in the subject and message boxes, it'll post- then it looks and acts like any other blog!
Sound waves travel in any kind of media- some much better than others but sound waves can't travel in a vacuum because there's nothing there to allow a sound wave to propagate through it! Just because no one is there to hear the sound waves a falling tree makes, doesn't mean they don't exist!