Here is a link to an interesting article about the issues of measuring traffic from mobile devices and the short comings of the traditional web analytics products http://searchenginewatch.com/showPage.html?page=3629590
Of course, this article can't capture everything, but it missed one big point and the one I've been standing up for years on. While the article talks about the short comings of using java script based tracking (like Google Analtyics, Web Trends SDC etc.), it didn't talk about my standard recommended approach.
This approach means setting the user cookie at the server and not on the web page and recording this in the log file. Most mobile devises (to my limited knowledge) do accept first party cookies even if they won't execute most java scripts. So with the cookie controlled by the server and not the web page, you can track unique visits.
What I found most interesting from this article was the percentage of people who do some web browsing from their mobile devices in the use (19%). Here in Canada I don't know of many who except in an emergency would do any browsing (unless their phone supports WiFi). Of course the cost of data plans here is ridiculous hight when compared to the USA.
Regardless if this percentage is high or low, the reality is people are starting to surf from their mobile phones and we better be prepared to measure and analyze this traffic. Anyone who's attended one of my web analytics or WebTrends training classes lately knows I do reference this issue with mobile browsing and its growing impact on the world of web analytics.