Free release a considerable shift. http://www.bit-tech.net/news/bits/2014/07/24/apple-yosemite-beta/1
IIRC the Windows 8.x previews [possibly the 7 ones too] probably had similar legalese buried deep in the terms... I know from working there that apple is so paranoid it's tinfoil hat has a tinfoil hat on it but the 'don't tell anyone about this thing we're showing to everyone' seems pretty standard for pre-release stuff...
Which website was it that had the article saying that translucent windows were a sign that designers had simply given up? nevermind, found it: http://blog.agoeldi.com/2013/08/02/...-i-switched-to-android-after-all-these-years/