#1 - Jan. 7, 2011, 4:15 a.m.
You can find the latest patch notes here: http://us.battle.net/wow/en/blog/2011384
Below you'll find a log to track what is new in the latest version of the patch notes.
January 28 Updates: http://us.battle.net/wow/en/forum/topic/1827663465?page=1#6
January 24 Updates: http://us.battle.net/wow/en/forum/topic/1827663465?page=1#5
January 19 Updates: http://us.battle.net/wow/en/forum/topic/1827663465?page=1#4
January 14 Updates: http://us.battle.net/wow/en/forum/topic/1827663465?page=1#3
January 12 Updates: http://us.battle.net/wow/en/forum/topic/1827663465?page=1#2