One of the main reasons for the Firefox browser's successful seizure of market share from Microsoft's Internet Explorer is the desire to escape the inundation of PC-slowing spyware. However, spyware experts indicate that with its increased popularity, Firefox itself will become a target for spyware creators, who are already poking at the open source browser alternative.NewsForge | Experts predict Firefox spyware will show up this year
I reported a bug once, I bet it's still not fixed.
Say I add this bit to my homepage.com
Firefox will say it blocked a popup. If you opt to allow popups from this domain
you are allowing the popup it self to open popups and as they are the same popups they pop up untill your computer breaks down. Mine is really fast, it can open massive number of popups in little time.
After the popups are loaded the web dev(il) can forward the popup to any number of pages and earn good money for the 500 impressions per minute.
So you cant safly open popups at all.