Symantec IPS 2.0 browser extension information.

Hello security experts! I've been needing some help on getting specific information on the Symantec IPS browser extension that comes with Norton 360. I have been searching Google for specific information on the feature but really have not come up with any good results, so my next best option was to ask you guys.

Question 1: What does Norton IPS 2.0 specifically do in the browser such as Firefox 5.0 and how is this different from the standard Norton IPS that's already built into it's firewall?

Question 2: If I use a browser such as Google Chrome that Symantec IPS 2.0 doesn't support, what do a lose in security in such a circumstance?

Question 3: Norton IPS was triggered once since I've been subscribed to Norton 360, the explanation Norton gave me was that it helps plug unpatched holes in web browsers such as a zero day exploits, how does Norton know what exploits Mozilla has and how do they patch it?

This is really just a quest for knowledge for me. If I'm out line asking these specific questions you feel there is an easier way to get this information, please direct me where to go. Thanks!