Wolfram Alpha is a computational knowledge engine. It's an online fact finding service that answers questions directly, rather than presenting lists of suggested sources for the answer.
A new image identification service has recently been added to Wolfram Alpha's capabilities. You can upload an image, and Wolfram Alpha will do its best to identify what's in the image.
Image identification has huge implications for blind and partially sighted people, but for the moment the service is not accurate enough to be useful. Wolfram Alpha learns from experience though, so it will undoubtedly improve as more people upload images and provide feedback on the quality of the identification.