After a short time out ill introduce  the 12 pool fast Expansion build order! 
What I can say from my own experiences, is that this strategy mainly against Terran, 
but is also playable against Protoss. The primary aim is to gain an economic advantage which allows a optimal entry into the mid-game. This is the biggest pro in this build, 
but there are also some cons: 
this BO is extremely vulnerable to early rushes.
- 6-9 Drone
 - 9 Overlord
 - 9-12 Drone
 - 12 Hatchery
 - 11 Drone
 - 12 Spawning pool
 
Now you can follow with Queens, some spine crawlers and lings.
After this i prefer an combination of Roaches and Hydras, may some Banelings.