In Hollywood or Los Angeles, we sometimes reply to an invite with "Hollywood maybe" when we don't want to completely commit.
Q: Do you want to go to brunch tomorrow with my friends visiting from out of town?
B: Sounds ok if nothing better comes up, Hollywood maybe.
I'm so happy for you. #ISHFY should be used when you're slightly jealous, but want to tell someone you're happy for them when you really don't give a sh*t.
Friend: OMG I just got free tickets to see Beyonce!
You:#ISHFY *rolling eyes*