Just came across ThingLink tonight and it seems like a pretty versatile app. With ThingLink you have the ability to make your images interactive. Hover your cursor over the image above and you'll see what I mean.
Upload an image of your own or from Flickr, FaceBook, or a different web source, and then add content tags. Your tags can have text, sound, web links, videos, or you can even add an image in your image. Videos tags use YouTube, Vimeo, and TED, while images can be tagged from Flickr, Instragram, and more. You can make audio tags linking to SoundCloud, iTunes, and Spotify. There's a lot more ways you can tag an image, so take a look at the examples in their gallery.
ThinkLink images can be embedded on a webpage and shared with other editors. One of the first things I tried out was embedding ThingLink in a Google Earth placemark. It works! That might prove to be redundant but it could also be a quicker way to edit placemarks with more content links.
I don't know if Instagram was worth a billion dollars, but I can see a lot more uses with ThingLink.
Special thanks to iTeach blog for introducing me to this resource.