Facebook, Amazon, and Linkedin don't own their domains in Chinese
Chinese for "face book" is: 臉書 (according to google translate). If you go to 臉書.com, Chrome brings you to xn--rovv01d.com, which is an available domain.
"Amazon" in Chinese is: 亞馬遜. The 亞馬遜.com brings you to: xn--nlqs61nl3f.com (also available). "Linked in" is: 掛在. The 掛在.com gets you to xn--3dsp30a.com Available.
Weird. A webpage by hackerfactor explains some of it, but I don't really feel like reading it right now.