I installed and it switched the call that my website was making via wordpress - and switched it to the google cdn. OK, so far so good. But my website is still calling google's cdn a 2nd time. I thought this plugin would remove all subsequent calls (I can't figure out why my website is loading jquery a 2nd time).
You can see the 2nd call by going to http://www.webpagetest.com and run a test on http://www.plumsavings.com. Then click 'first view - waterfall' and search for the load times for 'ajax.googleapis..." Usually you will see the calls at #6 (the one Use Google Libraries switched me to) and the other at #15. Shouldn't this plugin stop the load for this 2nd try?