Hugo Barra, product management director of Android, introduces Google's low-cost computer tablet Nexus 7 during the keynote speech at Google's annual developer conference, Google I/O in San Francisco. Google unveiled its own branded Nexus 7 tablet computer Wednesday, challenging the Apple iPad and Amazon Kindle Fire, and opening a window to its online shop for books, movies, TV shows and more. (AFP Photo/Kimihiro Hoshino)