There's some overlap, but what impresses me is that they're doing camera tracking (hard) in near-real-time and automatically (even harder) on an iPhone. Camera tracking is used in feature film visual FX frequently, and it's usually a very manual and specialist intensive process with very esoteric (and slow) tools...
Its a bit hilarious that Microsoft hired PTAM author just to put him in ... MSN software group :D
What's also impressive to me is that Google's solution seems robust, meaning it does a good job in the face of outliers like lens flare, exposure changes, and the like. I see a lot of research with canned results where they optimize for the 6 or so clips they test with, but it's an order of magnitude harder to make it robust enough to release it as GA to the general public.