What does the chainring have to do with SRAM YAW I'm shopping for 110 BCD chain rings and I noticed that some of the SRAM ones are labeled "YAW FD only". As far as I can tell the derailleur doesn't touch the chainring so whats so special? Can I safely use this chainring with a shimano FD?

To quote SRAM on YAW: "The front derailleur cage rotates to maintain a consistent angular relationship with the chain. Yaw technology eliminates the need for shifter trim. As a result, shifts feel more direct, more precise, and combined with the new Red crankset and chainrings, delivers an unmatched performance advantage in front shifting."

According to Velonews, you can use the chainring* with a Shimano setup, but you might get some chain rub (scroll down to compatibility grades). If you are not running a SRAM Yaw FD, I'd probably just avoid these rings and get normal ones.

* See the "Swapping chainrings" section of the same article on issues with the small ring.