Some people prefer to keep their browser un-polluted by add-ons, and are perfectly happy with the basic browsing experience. But if you're one of those, you're missing out on some incredibly useful features. All modern browsers allow developers to create add-ons, and in the case fo Firefox there are thousands of such tools available, free of charge.
But how to decide which ones are worth trying? The answer is an uber-addon called AddonFox. It's an automatic installer for around 100 of the best-known and most useful FireFox addons. Download and run it, and tick the boxes that correspond to the add-ons you want. Or just choose them all. The program will then download and install your chosen options.
The AddonFox installer is only 0.25 MB, plus whatever addons you ask it to download. It needs Firefox, and either Windows or OS/X.
Get it from www.addonfox.com, from where you can also browse the full list of addons that it's capable of installing.