UCG - what's that?

I have (too) gotten the question about what the F is UCG?
It started with some girl being a bit mad at my überpretty sister Iva Insane and then wrote: "She thinks she’s so much better than everybody else. F**king Upper class goth".

 I can never say no to a good laugh so we had a blast about us being UCG's and joked a lot about us being like the goth version of the Hilton sisters!
We have this as our standing joke now, saying we use Gucci stockings as "German stockings" (my own word for ripped stockings) and such :)

I'm not really up to date on the brawl between this girl and my sis, but I have never noticed my sister being stuck up. To me she is very humble and have a sweet persona, unlike me, who is the cold hearted bitch from hell and only thinks about me, me and me.
I think UCG was a compliment :)