Animation Appreciation Thread #5

The Sakuga Wiki [JP] - http://www18.atwiki.jp/sakuga/
ANN Database - http://www.animenewsnetwork.com/encyclopedia/

Animation Blogs [Eng]:
http://www.pelleas.net/aniTOP/
http://aninomiyako.wordpress.com/

Animation Twitters [Eng]:
http://twitter.com/Duune99
http://twitter.com/kyouray
http://twitter.com/catsuka
http://twitter.com/raito_kun
http://twitter.com/americopun [JP]
https://twitter.com/honnyaku_blog [JP/Eng]

Animation Tumblrs:
http://cammadanar.tumblr.com/
http://unkoer.tumblr.com/ [JP]
http://americopun.tumblr.com/ [JP]
http://ganasu.tumblr.com/ [JP]

Previous threads:
#1 http://dis.4chan.org/read/anime/1291816034
#2 http://dis.4chan.org/read/anime/1314681601
#3 http://dis.4chan.org/read/anime/1325612276
#4 http://dis.4chan.org/read/anime/1336754773

what are they talking about?
Horidesk is Hiroyuki Horiuchi right?
https://twitter.com/ntso1986/status/242315114731163648

https://twitter.com/ntso1986/status/242317819776221185

I guess this is the topic of the discussion https://twitter.com/bahijd/status/242315011249278977
anyone knows the source of this gif? Is this from the making of?