When Netscape lost out to Internet Explorer in the Browser Wars, it didn’t die. It went to Mozilla Foundation, and changed into Firefox, a browser that is much better than Explorer, which shows in its growing market share (now up to about 25 %, and about 60% of heavy users, like me.)
The best thing about Firefox was the Tabbed Browsing, where you can load lots of pages at the same time, and look at one while others are loading. The tabs at the top of the window allow you to choose each page, instead of going to a completely different window. This feature was so good the Internet Explorer copied it.
The best thing about Firefox is that you can customize and extend it to do many different things, with thousands of free add-ons available from the web site. Play music? Find stock prices? Add a Delicious bookmark? Almost anything, and all for free. People write this software for free, too. More on that in another tool.