I recently came across a site that wouldn't allow me to middle click a link to open it in a new tab, and a right-click didn't present any link-based options (save link as, open in new window/tab, etc etc). I decided to view the source to see what magic they were using and came across this method:
<span class="dlink" onClick="window.location.href='http://www.example.com'">Link</span>
This is really dumb. They're basically forcing the user to navigate away from their site, providing no method of open the target in another tab or window, all for the sake of (no doubt) being different and "cool". I guess it's kinda like those sites that use java and flash for things that can be done in basic html or html with a tiny piece of javascript.
For reference, there was no "protected" content on the source or target sites, and there was no problem with referrer urls.