http://helloworld.group.javaeye.com/group/topic/23435
http://cloud.csdn.net/a/20110303/292969.html
http://gihyo.jp/dev/serial/01/various-nosql/0006
http://www.exgear.jp/blog/2010/11/php-session-mongodb/
http://d.hatena.ne.jp/nazone/20091126/p1
