When you have such a great moment that you have to post a status on facebook instead of twitter.
Fernando: Bomb, I just got an A on my test!
Alejandro: Cool bro, you should tweet "Just got an A on my test #intelligence"
Fernando: Nah, this is too cool for twitter. It's status worthy
When someone uses a hashtag on facebook, much to the annoyance of his/her friends. Usually results in unfriending of the person and or burning down of their house.
Facebook:
Fernando: Just got my license! #elated
Alejandro: stfu. Status tweets are not allowed.