Airplay mirroring works great for apps (mostly video-related ones) with native Apple TV support, but for other apps - most notably Hulu Plus, it will only show letterbox on my 16:9 plasma TV. Again, my movies, tv shows and in-app videos like in CNN where there's a built-in AirPlay support will fill my widescreen, but apps that don't (Hulu Plus ... More @Wikipedia
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