This help topic is somewhat technical.
When a browser visits your web site, it specifies a tag that identifies itself. Here are the tags outputted by three web browsers:
Internet Explorer: Mozilla/2.0 (compatible; MSIE 3.02; Windows 95)
Netscape: Mozilla/4.05 [en] (Win95)
Opera: Mozilla/3.0 (compatible; Opera/3.0; Windows 95/NT4) 3.21
Note that both Internet Explorer and Opera include the "Mozilla" string in their browser tag. So, if you filter by "Mozilla", you will get several types of browsers.
The only safe way to filter for Netscape is to do the following:
Include "Mozilla" but exclude "MSIE" and "Opera".
Excluding Netscape
Exclude "Mozilla" but include "MSIE" and "Opera".