The idea is there should be significant overlap between what a cat classifier learns and what a dog classifier learns. So why independently learn two classifiers?
My paper on the Visual Memex got accepted to NIPS 2009 so I will be there representing my work in December. Be sure to read future blog posts about this work which strives to break free from using categories in Computer Vision.
On another note, today was my last day interning at Google (a former Robograd was my mentor) and I will be driving back to Pittsburgh from Mountain View this Sunday. Yosemite is the first stop! I plan on doing some light hiking with my new Vibram Five Fingers! I've been using them for deadlifting and they've been great for both working out and just chilling/coding around the Googleplex.