Q: Anti virus software (Norton) and 10.8.2

I just migrated from a Windows-based machine, so my first inclination before all else was to get myself an antivirus software.  It turns out I may not have needed anything at all - moot.

I'm seeing a lot of mention in this community of Norton antivirus products "damaging" your Mac.  What exactly does this mean?  Is this damage "irreversable"?

I did full retail for this product so I would rather not abandon it.

Any information/advice would be appreciated.