While I’ve never thought about using emotions to browse the Internet, apparently Emotiv EPOC’s brain-reading headset will do the trick for you. Combined with the EmoLens app, the EEG headset can detect up to four different emotions. Depending on how you feel, photos will be tagged differently.
If you tired of a machine judging your emotions, then you can use a combinations of concentration states, blinks, and shakes of your head to control the browsing and tagging process.
The EPOC neuroheadset is designed to let you control your computer with your mind. It actually not only detects brain signals, but also has a gyroscope on board for detecting your position as well.
The Emotiv EPOC and EmoLens app are currently available for purchase. The headset will set you back $300 (USD) while the app will cost you $40. Flickr is only one of the applications available for the headset, there are several others here. While this all sounds a bit strange, controlling your computer with your mind and small head and facial movements could make be helpful for the physically-challenged.