Do you simply like to change and customize the color schemes on GUIs? Thunderbird offers various extensions for that too. Wish you could play music while reading e-mail? Check out the FoxyTunes extension. Need more Spam filtering? AdBlock Plus is a common favorite extension for junk mail filtering. Do you find yourself frequently doing business with foreign language speakers? Customize your Thunderbird with language dictionaries. What can I do with extensions?īecause Thunderbird is open source, there are many extensions available for download. Beyond Mozilla Thunderbird's inherent open source greatness, its ability to handle many e-mail and RSS feeds, and keep it all organized is the wonderful ability to customize Thunderbird with add-ons and extensions.