If you're wondering what a web browser is, it's the program you use to "get on the internet". If you have a PC, you have Microsoft's Internet Explorer already installed. If you have a Mac, you have Safari, and if you're not very tech-savvy, you're probably using one of those two, depending on what kind of computer you're sitting at right now.
Mozilla's Firefox has been around since 2004 (its progenitor is Netscape Navigator which was the most popular browser during the mid-90s). Google Chrome is the most recent (and as of January 2013, the most-used browser).
I won't bore you with more history and stats, but I will say that all browsers do their job well, and choosing one is a personal preference. The following reasons are why I choose Firefox as my primary browser.
Firefox is certainly king of one thing—extensions. Extensions are little pieces of code you can add to the browser to customize it and make it do more things. For example, the first extension I always install is called AdBlock Plus, and it does exactly what its name implies—it blocks ads from appearing on websites. Other extensions I can't live without include FireGestures, Image Zoom, PDF Viewer (UPDATED 2/27/13: Firefox 19 now includes PDF Viewer built-in), PriceDrop, and 1Password. 1Password is actually a separate application that remembers your passwords. The extension connects 1Password to Firefox allowing it to enter your passwords for you.
#3: Security Firefox's Plug-in Check
Plug-ins are, in some regard, like extensions, but a little more powerful. If you've ever heard of Oracle's Java, Adobe Flash, or Microsoft Silverlight, those are plug-ins. Plug-ins typically let you do things in your browser such as watch movies (Netflix uses Silverlight to do this. YouTube uses Flash.), and play games. You may have also heard that plug-ins, especially Java and Flash, are renown for creating security issues. In January of 2013, the Department of Homeland Security actually recommended users disable Java on their computers. Plug-ins are basically a necessary evil, and must be kept up-to-date with patches that fix security vulnerabilities. Firefox handles vulnerable plug-ins very well. Head over to Mozilla's Plug-in Check (it will work in any browser, actually), and it will tell you if your plug-ins are out of date, and will give you links to download the latest software. Not only is this handy, but Firefox has even gone so far as to prevent plug-ins from loading content until you, the user, click to enable them. Firefox calls this Click-to-Play, and it's a small, but intelligent step to protecting users.
Since 2011, Firefox has greatly increased the rate that it updates. It took 7 years to get to Firefox 4 in 2011. Since then, Firefox has updated to version 18, well within the span of 2 years. Updating at this speed, it's a good thing that Firefox automatically checks for, downloads, then installs it's own updates the next time it is closed, then opened. (It should be noted that Google Chrome updates in this manner, as well.)
Now that computers have become so inexpensive, and because people may have multiple computers (both personal and work), keeping your bookmarks and passwords synchronized across devices and computers can be a major pain. Firefox has built-in sync, which means, once set up, Firefox will update any changes to your bookmarks, passwords, and more to the "cloud", then send those changes to your other devices. Add a bookmark on one computer, then it shows up automatically on another.
A semi-secret feature of Firefox is the ability to set your homepage as a set of 9 tiles that can display your most-visited sites, or personalized to show your favorite sites in whatever order you wish. To do this on a Windows 7 PC, click the orange Firefox button, then Options, then Options again, click the General tab, under Home Page: type about:newtab. Now, whenever you open Firefox or create a new tab, you will see your most-visited sites ready to be clicked. You can customize this page by dragging bookmarks into it, then clicking the Pin icon to keep them in place.
#5: Where the Competition Falls Short BHO Overload
My biggest problem with Microsoft Internet Explorer is something called BHOs—Browser "Helper" Objects. I put "Helper" in quotes because they most certainly do NOT help. BHOs are similar to Mozilla Firefox's extensions, however, you will most often see them as toolbars in Internet Explorer. You have probably either seen someone, or been the person with tons of toolbars installed in Internet Explorer—so many, in fact, that they limit the amount of actual webpage the user can see. The biggest offenders tend to be the Ask.com toolbar, Yahoo! toolbar, and even the Google toolbar.
Let me make the following clear: You do not need toolbars! They hurt your browsing experience! They rarely ever help you! Uninstall them! All of them!
The worst part about toolbars and Internet Explorer is that many programs will try to secretly install a toolbar into the app. Next time your update your Java plug-in make sure the un-check the "Install Ask.com toolbar" option.
Google Chrome is great browser. Every once in awhile, I'll open it and use it for a bit, but I always go back to Firefox because Chrome just doesn't have the extensions that I can't live without. Nor does Safari. And Internet Explorer? Forget about it. Chrome has some similar features as Firefox; it can also sync your bookmarks and passwords, and it's very easy to set your preferences. But, in my personal experience around the office, Chrome tends to have more issues when trying to print. I'm not sure what the cause is, but, generally, opening the same webpage in Firefox, the page tends to print. If you like Chrome, great, use it, but keep another browser around for the occasional hiccup.