Ask HN: Patent your app's interface? (i.e. HipMunk's flight visualization)

One of Hip Munk's main value propositions is their unique interface for booking travel; while it wouldn't necessarily be easy to knock off HipMunk's tech, as other sites cherry pick features from Hip Munks interface the "unique" value of hip munk's tech does deteriorate.

I was wondering if Hip Munk, or any other web/mobile app whose differentiating factor is interface, patents the key/unique components of their interface in order to inhibit copycats, and provide additional value/security to acquirers?

Considering the recent trend of Apple et all "integrating" the best interfaces of their app ecosystems into their core software offerings, it seems to me this is an especially important question to any startup whose primary innovation is interface, and one I personally don't even know if it is legally possible.

Thanks!