A web browser is the program you use to surf the web. (A browser can also be used access and view content provided by servers in private networks.) to Most computers come with the software already installed. Macs are pre-installed with Safari and PCs are pre-installed with Internet Explorer.
Let's review browser currently available to you!
Chrome is a Google-engineered browser. It was released in 2008, is free, and open source. (See below for more.) As far as I know, it does as much as other browsers too, and more. (I don't use it. I'm waiting for my plug-ins—software added to enhance my browsing experiences—to catch up.) Chrome is said to have great security.
Firefox is the most popular browser. Released in 2004 and provided by Mozilla, the program is open source, which means Firefox is "liberally licensed" and the source code is available to users (this is usually unavailable and under copyright) so that improvements may be made to the software. (This is a very good thing.) Firefox's features include tabbed browsing, cross-platform support, phishing detection, an option to clear all private data, customizable pop-up blocking, and private browsing.
Internet Explorer is probably the default browser on your computer. It was introduced by Microsoft in 1995. It is immensely popular.
Netscape Navigator was released in 1994, by Netscape Communications, and is considered the first commercial browser. Netscape Communications is now owned by AOL. The browser's development ceased in 2008.
Opera is a browser preferred for mobile devices (people say that it is fast). (I'm sort of unimpressed.) It was released in 1996 by Norwegian-based Opera Software Company. Nintendo has a hold on the browser—it comes with the Wii and is the browser used for the DS and DSI.
Safari is Apple's default browser. (So if you have a Mac, Safari is probably on your computer.) Apple released it in 2003 with Mac OS X. Your iTouch and iPhones are also equipped with Safari. Here are some features!
Browser Informaion, W3C Schools
Web Statistics and Trends, W3C Schools
History of the web browser, Wikipedia
Free and open source software, Wikipedia
Features of Mozilla Firefox, Wikipedia
Day Two: No One Even Attempts Hacking Chrome at Pwn2Own Competition, Lifehacker