A couple of months ago, we helped you get started on your journey to browser perfection with our list of 20 must-have Firefox extensions. But the ability to tweak your browser is a double-edged sword. There are extensions best avoided – including some of the most popular.

Popularity shouldn't be the acid test to determine whether you should install an extension. The important question is whether it enhances your browsing experience without any nasty side effects. The good news is that the extension community is actually pretty adept at self-policing. Most extensions that are truly ‘broken’ (for instance, they crash your browser or suck up all your CPU power) either get fixed quickly or simply vanish.

But some extensions are ‘bad’ in unapparent ways or just don't provide enough benefits to be worth running. So, in no particular order, let's look at 10 to avoid.


This web accelerator has a ‘pre-fetching’ mechanism that aids your browsing experience but makes you a very bad web citizen. You land on a page and start reading it. While your system is idle, Fasterfox silently starts following links and downloading the destination pages. The idea is that if you then decide to click on one of these links, the page is already cached on your local machine and will pop up very quickly.

This is nice for you, but it can be an incredible waste of bandwidth - just think about how many links are on a typical page. Even if you don't care about bandwidth, there are reports that some systems administrators are now detecting the extension (and others like it) and blocking clients that are using it. While it is possible to use Fasterfox responsibly, it is best avoided unless you know what you are doing.


This extension is hugely popular and works as advertised, giving you control over which JavaScript, Java and other executable content on a page can run, depending on that content's source domain. You whitelist the sites you consider safe and blacklist the sites you don't.

If you really have a need for this kind of control, then you're already using the extension and will continue to do so. But for the average web surfer, constantly having to whitelist sites so scripts can execute in order to give you a fully formed web experience gets tedious very quickly.

NoScript certainly makes Firefox safer but it’s not worth the hassle. For some reason, paranoia seems to be cool among web geeks but, for the most part, it is totally unwarranted unless you're sending and receiving sensitive data. Most typical web surfers who install this extension remove it after the novelty wears off.