An Add-on for Everyone
Firefox has the most ways to customize your online experience specifically for the way you use the web. There are more than 5,000 Add-ons (little extras that augment Firefox to meet your unique needs) just waiting out there to help you do more, have more fun and be more creative online.
Want some specifics? Check out the examples below, then visit our Add-ons site for the full range of possibilities.
Alerts & Updates
With Add-ons from this category, you get the latest on the weather, sports or even eBay auctions. Real time info shows up right in your browser, no matter which site you happen to be on.
For Example: 
Keep an eye on your eBay trading whenever you are on the Web.
Try the Firefox eBay Edition by eBay Corporation
Photos, Music & Video
Turn your Firefox into a photo uploader, a music player and an all-around multimedia powerhouse. It’s like having a media control panel at your fingertips while you surf, work, email or research on the web.
For Example: 
Control almost any media player right from your browser.
Try FoxyTunes by Alex Sirota
For Example: 
Discover new sites, then connect with friends and share your findings.
Try StumbleUpon by StumbleUpon
Themes
Don’t limit your browsing experience to a standard design. Choose new colors, make the browser easier to use (with bigger buttons, for starters) or just pick a look that suits your fancy.
For Example: 
The theme for people who like it dark.
Try NASA Night Launch by mcdavis941