It was likely an attempt to encourage all sorts of passive aggressive message writing between housemates. Also, it was a nice way to wish teammates good luck before a big match!
And an excellent way to find out WHO THE FRICK TOOK MY SAMMICH!
On the right hand door, there was a large collection of word magnets for people to use to leave messages for each other or write epic poetry. Either one.
((Have fun Real RhyDin housemates!))