While I see @BronxWench’s directions above, normally I go to my profile and do it there. A prompt at the top of my activity feed reads “Write a public message on your own feed...” Click there and it becomes an edit box where I can put in...whatever, hit “Submit Status” when done. Now, it’s javascript making the change (prompt → edit window), so maybe that’s disabled? I’m guessing a script/ad-blocker is fouling this up. @Deadman, do you have something like U-block or no-script installed?