Learn and have fun.
An augmented reality app. When you see something while walking that you think is interesting, or you know an interesting fact about it, maybe you discovered something, etc., you just launch the app, point the camera at the object and annotate it with your insight. You can also check and see what others have contributed regarding this object or other objects around you (buildings, signs, flowers, etc.)
Help web publishers visualize concepts.
A repository and a service. The repository is a constantly expanding visual Wikipedia, where user upload their images (photos, infographics, videos, etc.) that explain or demonstrate concepts visually. Website publishers can use the service. All they have to do is include a simple code on their site, and every word that can be visually enhanced gets linked to the right visual aid. The user just has to hover over the word to see the visual.
Wikipedia is usually – as its name suggests – a quick look at a subject matter. What if you need a deeper dive into the subject?
A wiki dedicated to deeper knowledge. It follows the working of Wikipedia, but for a subject written in collaboration to be permanently published, it has to have a certain level of deeper knowledge and approved by an editor.