There are many of us who hate the new Facebook Share so much that we will not use 2013. We would have preferred to stick with NIS2012.
But I have just been told by Norton support that NIS 2013 keys will NOT work with NIS 2012 installations.
After using Norton for 10 years (and on 1/2 a dozen machines now), it looks like I`ll be going over to a new product in the next few months.