Why use Thunderbird?
Thunderbird will allow you to manage multiple email accounts from different providers (Protonmail, Gmail, Yahoo! etc ...) in one place on your Ubuntu box, all at the same time.
By using Thunderbird Mail, you will be able view your received email when no internet connection is available.
This can be very useful for people taking Ubuntu laptops into meetings and anybody who would like to be able to access important information or compose emails without having to go on-line (for example people taking laptops on trains/planes etc...).
In conjunction with that, by using Thunderbird Mail, you can also set up digital signing and email message encryption which otherwise are not usually possible with the normal provider's webmail interfaces.
What email protocol works best (IMAP vs POP3)?
When you set up Thunderbird to use one of your existing email accounts the viability of the solution for your needs may depend on what protocols your email provider has made available.
The two protocols you will see are IMAP and POP3.
In today's multiple device world, IMAP is a better solution than POP3. Unfortunately, some providers (such as Microsoft) currently only offer POP3 (though there is talk that Microsoft will provide IMAP support for outlook.com accounts at some point in the future).
Post Office Protocol 3 only allows one computer to download email.
In the vast majority of cases, these days people will want the ability to access their email from multiple devices. POP3 isn't designed for this.
Also, when you send email from a device, only that device can see that the email has been sent.
To put it another way, actions are performed on your local folders, not on the server.
IMAP to the rescue! Thankfully, some providers have made their email service available through the IMAP protocol (Internet Message Access Protocol).
This protocol performs actions on the server side and all devices sync with that.
So all your email is available on all devices, and there is also a consistent view of what email has been sent. IMAP is properly synchronized for today's multiple device world.
OK, so does my provider offer IMAP?
Here is a little table showing protocol support provided by some popular web-based email services:
To sum up, if your provider offers IMAP you should consider using Thunderbird for your email. If they only support POP3, you may also want to use Thunderbird, but a consistent view of your mail folders will not be possible if you use multiple devices to access your email.
If your not sure what protocols your email provider supports, Thunderbird will show you when you go to setup your account, as described below.
Setting up Thunderbird
Start up Thunderbird Mail by clicking on the "Mail" icon in the top right of your screen, then from the menu select "Mail" as shown in the image below (You may see "Set Up Mail..." if you've not used the application before, click on that).
You'll be presented with a window like that shown below, click on "Skip this and use my existing email"
You'll be asked to enter your name, email address, and password. Enter them (and decide whether you want your password remembered or not), then click "Continue".
As shown in the screenshot below, you'll now see that Thunderbird has fetched the required configuration for you.
Select IMAP for a better email experience (if it is available), then Click "Done".
Now click on your "Inbox" and your mail will be downloaded and syncronised with your email account (Gmail in this case).
If you've used the IMAP protocol, folders you create in Thunderbird to sort out your email will now also appear in your webmail interface and vice versa.
Note that if you want some of your folders to be only visible through the web interface and not with Thunderbird, you can usually tweak the settings per folder. For example, GMail's labels (folders) can be configured by clicking on "Manage labels" in the webmail interface.
Using Thunderbird to handle email from multiple accounts is easy.
As shown below, simply click on "File" -> "New" -> "Existing Mail Account...".
Then follow the same process as you did when you set up the first account.
You can use Thunderbird for loads of other stuff, there's a nice collection of add-ons (plugins) including "Lightning" for schedule & calendar functionality, and "Enigmail" for GPG digital signing & encryption purposes (which we will cover soon).
There is also a chat wizard which supports the following chat networks: Google Talk, Twitter, Facebook chat, IRC, and XMPP.
So basically, you can use Thunderbird as a central point for all your messaging needs.
The future development of Thunderbird
New functionality and features will be implemented by the opensource community.
Mozilla Foundation (The developers of Thunderbird) will be focusing on the stability and security of Thunderbird.
Thanks to Mozilla Foundation