I was on that thread and here is my recollection. There was some sort of incident on a plane or something. Some woman posted that she was worried about her husband because he was flying that day. She then proceeded to say that she would check back later after she took a shower.
We all wondered how much she cared about her husband if she was off to take a shower in the middle of a "crisis" where her husband could be in danger - it was a question of priorities.
After that, any time some sort of breaking news takes place, especially if it looks like it could be terrorist related, someone will post that they are off to take a shower or just post a shower picture.
Search for FReeRepublic Lexicon or go to my profile page and you'll find the updated (correct) shower definition.