The work MARK ING (obviously without the space lol) is changed to Oops!! by the censor.
If you try to write it with spaces in between the letters, or in any way try to trick the censor it's changed to Whoopsie Daisy!
It is deemed a tad rude to mark threads, which is why the word has been censored. Basically, if you're going to write something you might as well write something and not just mark, kwim?
Hope that makes sense!