When you sit down and look at web pages, you are using a web browser. This is the piece of software that communicates with web servers for you via the HTTP protocol, translates HTML pages and image data into a nicely formatted on-screen display, and presents this information to your eyeballs -- or to your other senses, in the case of browsers for the vision-impaired and other alternative interface technologies. Web browsers also appear in simpler devices such as Internet-connected cell phones, like many Nokia models, and PDAs such as the Palm Pilot.
The most common web browser, by a large margin, is Microsoft Internet Explorer, followed by the open-source Mozilla browser and its derivatives, including Netscape 6.0 and later. Apple's new Safari browser is gaining popularity on Macintoshes running MacOS X, and the Opera shareware browser has a loyal following among those who are willing to pay for the fastest browser possible, especially on older computers. The Lynx browser is the most frequently used text-only browser and has been adapted to serve the needs of the vision-impaired.