In case you are not aware, the new release of AVG anti-virus software, free and paid, includes a "Do Not Track" add on/plugin for your browser. Personally, I like it, not only does it block all analytics, it is also capable of blocking social sites, ad trackers, and so on. The default list includes:
Social Networks and plugins -
Facebook Social Plugins
Ad Networks -
24/7 Real Media
It also shows the number of services being blocked per page and who they are. And while the user can adjust the setting to allow/disallow, I suspect many may leave the defaults which basically blocks everything but the social links. While this is a boom for privacy advocates, I can see it having a negative effect on ad revenue and accurate analytics.