Depending on what you watch on TV or read in the internet, FU2 can mean a lot of things. For the most part, FU2 translates to a shortened profane repartee of "fuck you too." It'san expression that can be interpreted as an act of defiance-- say when the world reams you in the figurative behind, you can just shout back "Fuck you too" and go on with your life, refusing to let any obstacle stand in your path. Yes, "fuck' is a vulgar word, but sad as it is, the fact that it is so commonplace make people downplay it's vulgarity to a minimum.
FU2 is predominant in internet and SMS (short messaging service) lingo, where character limitations are imposed. Many people who encounter it immediately interpret is a sign to back off, or fight back even harder with twice the amount of verbal whiplash.
However, not all FU2 references necessarily translate to that obscenity. Some sites, like FU2.it translates to "face up to it" which is a rather positive, though tangentially relevant translation to FU2's usual definition. In this site, we shall explore how many ways the term FU2 is used, and its growing popularity.