New words in the Duden...
That's quite the mouthful! Someone else said that facebooken has also been around for years - I guess they can only update it so often!
Slang words and teenager-lingo come and go quickly. In order to make it into the "Real" dictionary, a word needs to show some staying-power.
After looking at dozens of castle photos, they do tend to look more-or-less similar.