Happened to stumble across this site today which is kind of amazing!
Its pretty simple. You open the page and can type whatever you want! I have been seeing people using it for different things, but its predominately used for letting others know who has visited.
Just thought I would share it in case you wanted to check it out.
Click here to sign my world!
Click here for the 'Your World of Text' website.
Edit:
Click here to view the source!