This sounds like the tips & tricks you see in Pagespeed/Yslow, moving it to a proxy, coupling it with something like SPDY, and mixing in some server side caching. Which is neat, and no doubt will achieve some speedups. But I don't know if it is as revolutionary as Amazon is trying to make it sound.
There are also some serious privacy implications here. I don't really know if I want Amazon to cache & potentially record all my browsing, especially since that device is something they can directly connect to all my personal info (purchasing history, CC number, home address, etc..).
To be fair, Amazon is doing what our ISPs do already: cache sites to deliver it faster.
Also, Amazon's privacy statement says you can make Silk a normal browser by selecting the "off-cloud" mode [1]. Off-cloud mode allows web pages to go directly to the device rather than pass through their servers. I'm sure most users won't know of this option but at least it is an option.
There are also some serious privacy implications here. I don't really know if I want Amazon to cache & potentially record all my browsing, especially since that device is something they can directly connect to all my personal info (purchasing history, CC number, home address, etc..).