For those who don't know who "Sabu" is: Sabu is an alleged leader of the hacking group LulzSec. He features prominently in the group's published IRC chats, and is a supporter of the "Free Topiary" campaign.

The Economist refers to Sabu as one of LulzSec's six core members and their "most expert" hacker.

http://en.wikipedia.org/wiki/Sabu_(hacktivist)