Web surfers are discovering new ways to customize their internet experience — by downloading "add-ons" to the popular Firefox browser that censor bad language, blot out inappropriate (or unwanted) images, and provide other curious services. Here, 6 of the more remarkable Firefox add-ons available:

1. Google Alarm
What it does: Alerts you with a "vuvuzela-like alarm" when your personal information is sent to Google.
What's the point? To offer constant reminders of just how much personal data Google is vacuuming up, says Eyder Peralta at NPR, though, in my experience, it was all a bit too constant. Around 90 percent of the sites I went to were being watched by Google and "the alarm ran all the time."

2. China Channel
What it does: Allows you to experience what it's like to surf the web in heavily-censored China.
What's the point? Helps you value a freedom we normally take for granted, says CNET. You find out exactly "what life behind the Great Firewall of China is like," complete with slow-loading pages and random websites "inaccessible for no discernible reason."  

3. BP Oil Spill
What it does: Blacks out the letters BP from any web page with digital oil spills.
What's the point? To keep the oil spill fresh in your mind, at least according to Frank Gruber of Tech Cocktail. This digital approach to "rallying support" for the clean-up efforts in the Gulf "could help raise awareness..."  

4. Timemachine
What it does: Gives any website the primitive look that characterized the internet's early days, replete with animated GIFs, crazy fonts and colors, and pixelated wallpapers.
What's the point? Timemachine is a piece of "art," claims designer Tobias Leingruber in an interview with Digital Tools. Though some think it's "useless and therefore meaningless," it does make people "smile and remember good times. And isn't that a meaning?"

5. Shaved Bieber
What it does: Deletes every reference and photo of ubiquitous 16-year-old pop star Justin Bieber.
What's the point? To give non-fans relief from the Bieber barrage, says Matthew Moore in the Daily Telegraph. The prospect of a Bieber-free internet experience is "likely to prove particularly popular on Twitter" thanks to the "incessant tweeting" of the pop star's fans.

6. Ctrl + F'd
What it does: "Censors" selected words and images behind rectangular boxes, as if they were redacted from "sensitive online documents."
What's the point? It can be quite useful when you want "to mess with your friends," says Greg Leuch at Free Art and Technology.