As with Firefox, you can extend Thunderbird's functionality by installing extensions. Mozilla's official extension repository has quite a few nifty tools on offer, and which ones you choose to install depends entirely on your needs. There are, however, a few extensions that you might find indispensable no matter how you use Thunderbird.
Although Firefox and Thunderbird use the same extension format (and some extensions works with both applications), installing extensions in Thunderbird requires a slightly different approach. First, you have to download the extension you want to install. To do this in Firefox, right-click on the link to the extension (i.e. the xpi package) and choose Save Link As. In Thunderbird, choose Tools -> Add-ons, press the Install button in the opened Add-ons window, locate the downloaded extension, and press OK. Once the extension is installed, restart Thunderbird and you are ready to go.
Once you've installed the XNotes extension, you can attach notes to individual Thunderbird messages. To add a note to a message, simply right-click on it and choose XNotes -> Create note. This adds an XNote tag to the message and creates an empty sticky note that you can mark up.
Quote Colors makes it easier to read messages containing multiple quotes. By default, Thunderbird marks quotes in a message with the > character. This works fine for one or two quote levels, but beyond that, it becomes increasingly difficult to read a message and locate in-line answers. Quote Colors provides an elegant and effective solution to the problem by applying colors and borders to each quote level and nesting quotes. Using the extension's preferences you can change the default color for each quote level, quote border settings, and other options.
As the name suggests, the Clippings extension allows you to save text snippets and quickly insert them into a message, which can save you a lot of typing. To create a new snippet, select the desired text fragment, right-click on it, and choose Clippings -> New From Selection. Alternatively, you can evoke the Clippings Manager by clicking on the Clippings icon in the lower right corner of Thunderbird's main window. You can then create a new clipping from scratch (press the New Clipping button), or from the text in the Clipboard (press Options and choose New From Clipboard). The Clippings Manager also allows you to edit the existing clippings and organize them into folders. Better yet, using the Options button, you can easily export and import your clippings, which can come in handy if you use Thunderbird on multiple machines, or you want to share clippings with other users.
If you are using Thunderbird's Address Book to keep tabs on your contacts, you might find the SyncMab extension useful. It allows you to export your address book either to a local file or to a remote server (SyncMab supports the FTP, HTTP, and HTTPS protocols) as well as import address book data from a specified location or server. This makes it a useful tool not only for backing up your address book, but also for keeping contact info in sync between several Thunderbird installations.
Using SyncMab, you can set up multiple synchronization profiles. For example, you can create separate profiles for saving the address book to your hard disk and syncing the address book with a remote FTP server. A word of caution: SyncMab doesn't encrypt the address book file, so it is better suited for use on a local network rather than a publicly accessible FTP or Web server.
If you communicate with people in different countries, knowing the current time in a given part of the world can be useful. If you want to keep keep an eye on the time in different cities, the FoxClock extension is the way to go. Once installed, it places a completely customizable world clock in Thunderbird's status bar. You can add as many countries and cities as you like either by choosing from the FoxClock's default list or defining your own "time point." The Options dialog window allows you to change other settings, including the way FoxClock is displayed, time formats, database update, and much more.
Every Monday we highlight a different extension, plugin, or add-on. Write an article of less than 1,000 words telling us about one that you use and how it makes your work easier, along with tips for getting the most out of it. If we publish it, we'll pay you $100. (Send us a query first to be sure we haven't already published a story on your chosen topic recently or have one in hand.)