Can someone tell me how AD is licensed?
Afiak it is just a subsystem of Windows Server thus requires no additional licenses. But there is some bizarre ass license subsystem (of Windows Server) that the summary refers to. I'd suggest reading the ToS.
IANA Windows SA.
Why is Slashdot so biased towards open source?
Becase many nerds have a 'hacker' mentality, where if they purchased a physical device they own it and can do anything they want with it, DRM, DMCA, vendor-lock-in and other such evils are viewed as evil because they inhibit hacking.
"Pay no attention to the man behind the curtain." -- The Wizard Of Oz