Firefox Firefox is an alternative to Internet Explorer; it offers a number of functions that IE does not, such as tabbed browsing, built-in search and pop-up blocker, customizability. There’s also Thunderbird for those of you looking for a replacement for Microsoft Outlook. Firefox is definitely worth trying out! Mozilla is a global community dedicated to building free, open source products like the award winning Firefox web browser and Thunderbird email software. add-onsblockerbrowsercustomizeemailffirefirefoxfoxfoxfireinternetmozillaonlinepop-upsecurespeedthunderbirdweb with system:unfiledby 11 users