I have recently encountered this text in which the author claims very high MySQL speedups for simple queries (7.5 times faster than MySQL, twice faster than memcached) by reading the data directly from InnoDB where possible (MySQL is still used for writing and for complex queries.) Knowing that faster DB is always good, I thought this would be an interesting thing to consider :)
http://yoshinorimatsunobu.blogspot.com/2010/10/using-mysql-as-nosql-story-fo...