It happened a bit of spontaneously, so noone was invited. It was my first try, to make introduction to yaml for php prgrammers, and if there is more interest I will give another talk which will cover more details, this time with proper scheduling :)

You can check out the log of the discussion for his entire talk (covering topics like what YAML is, where to get more information on it, some of its features, and a mention of the Syck library for parsing it).