Mozilla Firefox

Internet Explorer's decline in popularity can be directly attributed to the rise of spiffy alternative browsers such as Mozilla Firefox. Long known for providing a more secure surfing experience than Microsoft, this top-rated browser has an extremely potent pop-up blocker that's become one of its calling cards. Even though IE eventually ponied up with its own ad-stopping features, it still lacks the convenience of tabbed browsing, a perk Firefox hasn't neglected. If you haven't already hopped on the alternative-browser bandwagon, this is a fine place to start.