I believe Silk is entirely different from attempts by competitors; there is little post processing on the mobile device, dynamic pre-fetching and web page re-formatting to scale; not mere compression and decompression.
Google was mostly a proxy server (well it was pre-Chrome and might deserve another look by Google), Opera does nothing very original, most browsers can request compressed pages for transmission by most servers, but then they must be decompressed by the browser after reception, so it increases processing time on the PC even though it speeds transmission from the server.
...Like Amazon Silk, the Opera servers compress the webpages as it processes them, to as little as 10% of the webpages' original size, making it faster and cheaper to load each page,"... it is possible to use Silk in an 'off-cloud' mode but which "allows web pages generally to go directly to your computer rather than pass through our servers Opera Answers Amazon's Cloud-powered Silk Browser | PCWorld...Google tried something similar back in 2005 with their Web Accelerator Plugin. While the plugin is no longer available, the support documents still are. Google discontinued support in early 2008 after a number of issues arose — similar issues that are likely to be faced by Amazon with Silk. Why Silk won’t be silky smooth for Amazon — Tech News and Analysis
