There are still plenty of great reasons to use a desktop email client</a. While Thunderbird has slowed development, it's still our favourite consumer email client for Windows and Linux. Whether you're still using it or want a way to supercharge it with features available in other hotshot desktop email apps, here are the add-ons to install to make Thunderbird even better.
There's nothing wrong with webmail, but if you want complete control over how your mail is handled, filtered, organised and secured, a desktop client is the way to go, and Thunderbird is one of the best. This collection of plug-ins makes it even better.
Thunderbird Conversations is one of our favourite extensions for Thunderbird. Put simply, Conversations gives you Gmail-style threaded conversations in Thunderbird's message preview and message windows. The add-on offers a regular conversation view that pulls messages from multiple folders even if you have part of the conversation filed in one place and another part in another, quick-reply that lets you respond to a message in a mini-reply window at the bottom of the conversation thread or open a new window to respond,, auto-completing email addresses for participants in the conversation, and more. Once you've used Thunderbird Conversations, you'll have a hard time going back to the default view. Many reviewers note that it really should be part of Thunderbird's default UI, and we agree. It's not perfect, and there are some open issues with it, but we think its benefits outweigh its drawbacks.
Filelink is Thunderbird's built-in cloud attachment feature. By default, it supports Ubuntu One, YouSendIt (now called Hightail), and Box. Those are all great services, but Dropbox is the cloud storage juggernaut. Dropbox for Filelink seamlessly adds Dropbox functionality to Thunderbird for outgoing attachments. Your recipients will get links to download the files you want them to have, and galleries full of the images you want them to see, instead of stuffing their inboxes with huge files and images that take forever to download and view.
If you have rolled your own cloud storage service using something like OwnCloud or have a web-accessible NAS, and you have WebDAV enabled, you can use WebDAV for Filelink to attach files from your personal cloud or NAS to your messages. Your recipients will receive links to download them or view them (you might want to warn them so they're not put off by an unusual URL at the bottom of your message!)
As its name implies, Send Later allows you to compose a message and then schedule it to send whenever you want it to go out. Perfect if you want to send a message to someone on the other side of the world when you know they'll be awake to read it, or if you want to give yourself a little buffer time between writing an email and sending it to make sure you actually want it to go out the way you wrote it (perfect if you're the type who types angry, hasty replies). The add-on works with Thunderbird's built-in "Copy to Outbox" feature, and gives you the choice to send in 15 minutes, 30 minutes, two hours, or to specify a time and date for each message.
If you're familiar with the little arrows next to a Gmail message that shows you whether the message was sent directly to you, CC'd to you, or sent to a list that you're a part of, you already understand how indicators work in Thunderbird. Once installed, you'll have to add the indicators to your message list, but they don't take up a lot of space and you'll be able to tell at a glance which messages were sent directly to you, and which ones, for example, you can safely ignore because they were sent to a massive mailing list or a group of people. You can even sort by them to go right to the personal messages first. It's also a great way to weed out the people who consistently send group messages instead of direct replies, or a way to make sure you're not replying to everyone when you should be replying to one person.
If you're a fan of Markdown, the super-simple way of editing and formatting text, you can bring it in to Thunderbird with the Markdown Here add-on. Once installed, the extension allows you to compose your email in Markdown, then just right-click anywhere in the compose area and choose "Markdown Toggle." You'll see it marked back up into HTML, the way your recipient will see it when they get it. If you like what you see, go ahead and fire it off. If not, toggle it back and keep working on it. Your recipient won't know you used Markdown to format the message, and they don't need to know Markdown to read or respond to it.
Lightning is a calendaring add-on for Thunderbird. Most email clients have some calendaring functionality built-in. With Lightning, Thunderbird gets its own rolled in calendar, and while it's not the most feature-rich calendaring tool, it's come a long way. Combined with the Provider for Google Calendar add-on, you get bi-directional access to your Google Calendar, so all of your Lightning events go right to your Google Calendar and vice versa. It's the next best thing to having Google Calendar right in Thunderbird.
It's not perfect -- you only get access to one Google Calendar, and it can be a little buggy as the developers behind both extensions struggle to keep up with Thunderbird updates (even at their current slower pace) and Google tweaking Calendar behind the scenes. In any case, If you like adding appointments from your email right to your calendar, getting alerts in your email client for upcoming appointments, and responding to event invitations right from your email client, you don't have to give up Thunderbird in order to get the flexibility of Google Calendar. These two add-ons will deliver it to you. If your organisation uses MIcrosoft Exchange instead, or you want compatibility with Outlook calendars, you can try this version of the Exchange 2007/2010 Calendar and Tasks Provider, which works with the most recent version of Thunderbird (the official, non-beta version of the same plugin does not).
Previously mentioned TorBirdy automatically connects you to a Tor proxy server when you log in to your email, so all of your Thunderbird traffic is anonymised through the Tor network. It definitely adds a little overhead to getting and replying to messages, and things that may be faster without Tor in the picture are a little slower, but if you're sending email and you don't particularly like the idea of your location being tracked via message headers, this will do the job for you.
It's important to note that TorBirdy anonymises outgoing mail (and even read receipts, since they're essentially auto-replies), but like any Tor traffic, it doesn't really make you anonymous to your mail provider -- and there's no reason you'd want to be, you are checking your email after all. This is really for those situations where you want to send an email to someone and don't necessarily want the message headers betraying where you're located or what ISP you're using. TorBirdy also supports Enigmail, which we'll get to in a moment.
Enigmail is a security extension for Thunderbird that uses OpenPGP to encrypt and digitally sign your email messages. It works like a charm, and it's relatively easy to install and set up. You do have to do some leg work to get it up and running (you'll need to install GnuPG and set it up yourself, but Enigmail has a great quick start guide to get you up and running quickly) but once you have it configured, you can leave it alone and trust that any outgoing messages you send are encrypted and safe from prying eyes at your email provider, anywhere along the way, or even on your recipient's end.
Development on Enigmail has largely stalled, but that's not too much of an issue considering is still works well. There's plenty of documentation, forums and mailing lists for it, so if you run into problems, someone has probably already found a solution.
These plugins add some pretty beefy features to Thunderbird, some of which aren't available in fancier, paid email clients. If you're not ready to shell out for Outlook, Postbox or Sparrow (even though it's been purchased by Google), and some of the other clients we've mentioned lately like previously mentioned Inky, the good-looking but Mac only Airmail, or the promising but feature-poor Mailbird don't look ready for prime time to you, these add-ons can give Thunderbird a whole new lease on life. If you haven't looked at Thunderbird in a while, take a look and install some of these. You may be happier with it now than you ever were.