is everyone trying to pose as lady gaga now?

I wouldn't say pose.

They're inspired by Gaga, I mean, they don't dress/act EXACTLY like her, but they're going a bit more.. crazy. If you know what I mean.

e.g. Rihanna, Christina Aguilera, Beyonce and others have gone for a different look, different music videos etc.

But Lady Gaga was inspired by lots of other artists as well, Madonna being one of the obvious ones.

So yeah, I wouldn't say posing or copying, just inspired, and then following the trend.