The concept of Mozilla going IPO has received some excellent analysis recently.   

While Firefox's world-wide penetration hovers below 20% depending on the report, The Industry Standard user-base overwhelmingly support the browser by a whopping 43,44%, just a hair above the combined totals for Internet Explorer 7 and 6.  

With Firefox's share growing each day, this prediction is that Mozilla will IPO some time in 2008.