Adblock Plus is an add on for Mozilla Firefox and Google Chrome that stops annoying pop up ads. It is free and works extremely well. On Youtube, it allows you to avoid the annoying banner ads, commercials, and other ads which detract from your browsing experience. On Facebook, it stops the clutter on your page.
Now that I have been using Adblock Plus for the last six months, I don't think I could ever go back to surfing the web without it. While I appreciate the fact that Google and Facebook are giving me "free" services by forcing me to look at ads, Adblock Plus gives me a break from these annoyances.
I don't recommend Adblock Plus for Android. It is too overzealous and blocks legitimate pages you might actually want to see. The ads in mobile browsers like Google Chrome and Firefox aren't overbearing anyway. If you are a Windows or GNU/Linux user, Adblock Plus will make your desktop browsing experience much more sane.
While the web is fun, it is also a dangerous place for those who click on the wrong ads. Sometimes you can acquire a malicious program simply by going to a website. Most viruses come from opening email attachments infected with malware and viruses. Taking measures to protect your computer from the annoying frustrations of slow downs, pop ups, and other problems can save you time and your pocketbook, particularly if this saves you a trip to the Geeksquad to clean your infected computer.