Secondly, I've uploaded new replays that reflects an improved build order that involves chronoboosting out 2 probes before putting down the forge. As you can see in the replay, it works quite well.
I've also uploaded a replay where I decide to play the game out after I don't bust the wall, and instead choose to drone up. The result is astounding. There's a 30 food advantage for the protoss player at the 8 minute mark. He then kills me shortly thereafter. If you watch the replay, I don't catch up in econ until halfway through the game, and Fingo is able to maintain the 30 food lead while teching up to templar. Granted, I played poorly that game, but the point is that a 30 food advantage after your opponent 6 pools is better than anything any toss going 10 or 12 gate could achieve.
If you watched the GSL from last night (Fruit Dealer vs. Inca) you'll see how devastating a 6 pool is if you only try to use probes/zealots and a "normal build (12 gate, etc) to hold it off. It's hard, and you could lose outright. Why would you choose a response that has even remotely a chance to lose when you can instead respond in a way that guarantees you a 30 food advantage going into the mid game, with a push that can often kill the Zerg outright? I just don't understand it.
Disclaimer: This is a guide for Steppes of War. On this map it's almost impossible to stop a 6 pool with even a 10 gate without taking Probe losses, due to the Zealot nerf. This would work on other maps as well (except Scrap Station), since you'd have a little more time to respond.
My friend Fingo and I were talking about how powerful 6 pool had become in ZvP since the zealot nerf made it pretty hard to stop a 6 pool with even a 10 gate. So, we started working on build orders that would survive a 6 pool while still being ahead in econ (i.e., not losing any probes). In the end, we discovered a build order that stops a 6 pool cold with you being 15 probes to his 6-7 drones (depending on how many drones the zerg decided to build, and whether you decide to squeeze out 2 extra probes), without having to scout ridiculously early. All credit goes to Fingo for finetuning this build order.
P.S. Fingo is 1600 diamond, and I am 1400.
The Build Order
Probe until 9/10
Scout immediately after pylon
See 6 pool, return with scouting probe
10/18 Chrono Probe
11/18 Chrono Probe
12/18 Forge at ramp
12/18 Begin cannon and Gateway, using the cannon to block the space between the Gateway and Forge
12/18 Resume Probe production
At this point, the lings should be arriving at your ramp. If the Zerg is smart about it, he'll choose to focus the Forge, but it doesn't matter if he focuses the Gateway either. Your Gateway/Forge will probably fall (or come close to dying), and it is essential that you pull probes at this point to block the remaining lings he has, especially if you went with Version 2. You shouldn't lose any probes because the cannon will have come up by then. After you finish off the lings with 0-1 Probe losses, you should be 14-15 probes to his 6-7 drones. Now, rebuild your wall. You've won!
A Photon Cannon teabagging a Zergling
Replay 3 (Where we play the game out after I choose not to bust, and drone up instead)
We did a couple variations of this build order. In one variation, Fingo cut the 2 chronoboosted Probes in favor of a pylon block and a faster Gateway. This method still leaves you ahead quite a bit economically, and is also a little safer.
In our replays, I also tried a few variations of the 6 pool, including one replay in which I pulled all my drones to completely all-in the Protoss. The drones don't do much except inflict more Probe casualties.