Norton IPS 2.0 Extension on Firefox 3.6.3

In simple terms, tell me what the Norton IPS 2.0 extension does and why I should use it with Firefox 3.6.3.  And, if not, is there a technical reason why it can't be removed, just deactivated.   I prefer to "control" the extensions used with Firefox and I do have a problem being "forcefeed" with extensions of any kind.  Thanks.