Apple’s voice activated virtual assistant is only available on the iPhone 4S, but now it would appear that Siri may have a competitor in the form of an iOS and Android app called Evi.
Evi works in a similar way to Siri, you press a button on the app and ask it a question, it will then respond to you with an answer, and it works in a similar way to Apple’s Siri.

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Original Story Evi To Take On Siri On iOS And Android (Video)
Evi To Take On Siri On iOS And Android (Video)
(Via Geeky-Gadgets.)