from wikipedia...you got me interested...
For simplicity, the word Mozilla is often used to refer to all Mozilla-based browsers. For example, when it is said that a website is usable by Mozilla browsers, it means that it is usable by Mozilla Suite, Firefox, Camino, Netscape 6, etc. In some older Internet statistics programs, the term "Netscape 5.x" is incorrectly used to refer to these browsers because the user agent string starts with Mozilla/5.0.