Just wanted to commend this amazing framework, it has made my job much easier and more fun then it otherwise would have been!
I have developed Jobspace using Yii, as well as a few other classified sites (you can see in the links at the top of the page).
All sites using the same codebase.
In addition I am developing a social network (Livespace) for South African market.
If you see any errors or bugs I will be happy if you could inform me.