Power Nap Limitations
I turns out that Power Nap is only available on MacBook Air (Late 2010, Mid 2011, Mid 2012) and MacBook Pro (Retina, Mid 2012). As a Macbook Pro (13 inch, April 2010) user, I'm really disappointed. I was really looking forward to this feature.
I'll probably end up upgrading to a 13 inch MacBook Air if it gets upgraded with a Retina Display next year. Between not getting this feature and AirPlay mirroring, my computer is starting to feel somewhat old.