Quite common Australian term indicating an entire lack of something. Often used in the context of knowledge:

"Davo knows bugger all about anything mate!" indicates that Davo (a common contraction of David) is the proud owner of a quite limited knowledge base.

"What are you doing Davo?"
Davo: "Bugger all" read - nothing
Well, what would we expect from Davo?

We are a country with its roots in Rum, Sodomy, and the Lash. It's little wonder then, that the word bugger plays a big part.