So, I noticed there was no mention of multi-touch events in the video, and none of the apps demonstrated used multi-touch. I did some digging to see whether this was a gap or whether mozilla had been working on multi-touch in browser (since the consequences of such a change for JS APIs are interesting to consider).
Mozilla has apparently been working on multi-touch in browser as one can see in these two links:
It is possible they see their OS as being suited for one-handed devices. One of the things I do not like about Ice Cream Sandwich on my Galaxy Nexus is Google has removed the "+"/"-" buttons in most of their native apps so now I have to either use some really unwieldy one-handed finger contortions or use two hands to zoom in and out. I think an argument can be made that in many instances at least on a smart phone as opposed to a tablet multi-touch while being fun to use is actually a step backwards in usability.
Mozilla has apparently been working on multi-touch in browser as one can see in these two links:
http://hacks.mozilla.org/2009/08/multi-touch-firefox/
http://hacks.mozilla.org/2009/10/multi-touch/