Outbound Links is a plugin I wrote some years ago to force all outbound links to open in a new window. We can discuss to death if it’s a good thing or not, but why not to try?
The plugin can also track via Google Analytics all clicks on outbound links and them can be saw foltering the content statistics with “/out/”. Clearly, if you track such click, your statistics willbe “polarized” as each click is counted as a page view. The unique visitor are not affected.
If you need to ask something about this plugin, please leave a comment here.
Outbound Links is published on WordPress Plugin Directory: download it here.