Be sure to check 4chan boards
http://boards.4chan.org/sci/res/5414358#p5427185
HACKFORUMS
http://www.hackforums.net/showthread.php?tid=3162666&page=2&highlight=cicada+3301
http://www.hackforums.net/showthread.php?tid=3152843&pid=29443767#pid29443767
UNIFICTION
http://forums.unfiction.com/forums/viewtopic.php?t=36893
GERMAN COMMUNITY
http://www.allmystery.de/themen/it83189-14
REDDIT
http://www.reddit.com/r/codes/comments/163lgo/cicada_3301_round_ii/
http://www.reddit.com/r/cryptography/comments/16e6n8/cicada3301_is_back_and_things_are_weird/
PiraX forum:
http://cryptoforums.net/showthread.php?tid=1&pid=1#pid1
XKCD
http://forums.xkcd.com/viewtopic.php?f=2&t=99688&e=0
http://krautchan.net/int/thread-15529651.html
Add links if you find any