This is a short analysis on how web analytics are implemented across a few top trafficked websites. Part of them were picked from the Alexa rakings for shopping websites and some are the homes of popular tech giants.
I tested this in Mozilla Firefox with a spoofed iPhone 3 user-agent (via the User-Agent Switcher plugin). The drawback of this method is that for sites using feature detection and client-side redirection versus redirection based on the UA string I would still be getting the desktop site. That being said, I didn’t find any of the sites to have this behavior.
Also, I didn’t check all of them with a featured phone UA. I only did this for sites that had clues to different enhanced/featured implementations in their URL structure. The only one that had this, from the sites I tested was Groupon.
I used Firebug to check the requests being made and the size of the scripts. I also used the online JS Beautifier and the closure-compiler interface to swing back and forth between minified and unminified scripts.
I tried the domain of the companies directly (i.e., canon.com) and I did not navigate deeper into the site structure for any of the tested websites. It may be possible that some sites who reported to not have a mobile optimized site to simply not redirect to it when accessing them directly.
Apple, SAP, Canon, Asus, Toshiba, Fujitsu and Acer do not serve optimized content for mobile - or at least I was not able to find their mobile site given the methods described in the beginning.
I posted the code used to generate the chart in a gist. Feel free to update/correct it.