If you're reading a document, and click a link it contains, then Windows will usually open your default browser. And normally that's fine, but sometimes, just occasionally, you might like a little more choice.
Maybe the site only works in Internet Explorer, for instance. If there are security concerns that you might want to open it in your NoScript-protected copy of Firefox. Or perhaps you'd like to use Chrome for its sheer speed. But Windows doesn't have the flexibility to let you decide, so you open in the default browser, copy the URL, open the browser you really need and start viewing the site. Annoying? Yes, and that's why Browser Chooser offers a different way.
Launch the program, and you'll need to spend a few moments populating its stylish toolbar with icons representing all your installed browsers. Once that's done, Browser Chooser installs itself as your default browser, pops up every time you click on a link, and invites you to select the most appropriate browser. All you have to do is click once on the relevant browser icon, and it will open and display the linked page.
This releases you from Windows restrictive "one browser for everything" policy, then, but does introduce a lesser hassle: you'll need to make an extra click every time you go online from a document link. If you generally use one browser anyway then this may make Browser Chooser seen not worth the trouble of installation, but keep in mind that there is a small security benefit. If a malicious document on your PC launches a particular URL, then instead of a browser automatically opening and perhaps infecting you with something, Browser Chooser will open instead. You can then recognise that you've not clicked a link, close Browser Chooser without clicking an icon, and keep your PC malware-free.