Whats the true meaning of Anonymous Mask?

[Devon]

I was wondering whats the true meaning behind the mask and symbols because I've been interested and posting images of it on my social media ( Twitter and Facebook)

[Jim Gatz]

It's from the movie V for Vendetta

[loudrock256]

The mask they use is the Guy Fawkes mask.

He became a symbol for rebellion and anarchy after he tried to blow up parliament, and was hanged soon after. Anonymous sees their work similarly as a just rebellion, and they're not very organized or law-abiding (i.e. anarchic). It's rather fitting.
The other ? symbols they use simply allude to being anonymous and unknown- they're not a single person or organized group, they're just anonymous.