How do you digitally communicate when you want to your messages to be private, not public? Options include texting and chatting, within an app, program, or Web-based service, and using your smartphone, tablet, or laptop or desktop computer. You can even email.

Email is the oldest of these technologies, and it’s still a viable medium today. Chat requires you and your correspondent or correspondents to be online at the same time. Text typically is interruptive, alerting your recipient that a new message has just arrived. But email, depending on how you set it up and your habits, can be read and responded to at will.

Mozilla, the foundation behind the Web browser Mozilla Firefox, recently raised eyebrows when it announced that it wanted to shed itself of Mozilla Thunderbird, its free email program. Thunderbird was popular in the years after its release in 2004. But it has fallen on hard times lately with cloud-based email services such as Google’s Gmail and smartphone-based email apps such as Apple’s iPhone Mail siphoning off users.

According to Litmus Email Analytics, Thunderbird currently has only a small percentage of the email market, in tenth place overall. The ten most popular email apps, services, or programs in order are:

1. Apple iPhone Mail 
2. Google Gmail 
3. Apple iPad Mail 
4. Google Android Mail 
5. Microsoft Outlook 
6. Apple Mail 
7. Yahoo! Mail 
8. Microsoft Outlook.com 
9. Microsoft Windows Live Mail 
10. Mozilla Thunderbird

Observers have weighed in on the reasons behind Thunderbird’s difficulties, including its neglect by Mozilla. One core reason appears to be the declining popularity of desktop programs in general.

Since the release of the first IBM PC in 1981, using a desktop or laptop PC and an email program residing on it used to be the only way a typical home or small business user could exchange email. But email existed before the IBM PC and previous home computers such as the Apple I and II, the Commodore PET and 64, and the Tandy TRS-80. Early email was based on mainframe computers.

The first email message was sent by U.S. Department of Defense contractor Ray Tomlinson, to himself as a test, in 1971. Email was standardized by RFC 524 in 1973 through the Internet Engineering Task Force and the Internet Society.

Popular email desktop programs, or clients, over the years have included Pine, Eudora Pro, and Pegasus Mail. Many people today still use their laptop or desktop PC to exchange email, even when using webmail services such as Gmail. This is one of Thunderbird’s many tricks. Pegasus Mail is still around as well.

Email has spawned or contributed to a number of important societal phenomena. With the sometimes hundreds of emails that some people receive every day, including unwanted commercial emails or “spam,” email has played its part in information overload. Today’s email programs and services, though, do a good job of helping you filter out what you don’t want, with Gmail being particularly good for spam.

“Email bankruptcy,” also called “email fatigue,” are terms coined to describe getting so backed up with the email in your inbox that you need to do a large-scale deletion of unread emails. Setting up your own filters can help, letting you prioritize important emails over less important ones.

Email is one of the vectors of computer viruses, with email attachments being the culprit. Never open an attachment from someone you don’t know.

Phishing is the process by which crooks send emails with links to fake websites to try to steal your credit card or other information. It’s always better to go to websites yourself from within your Web browser.

In its recent announcement, Mozilla has said it will be trying to find a suitable new custodian for Thunderbird, a company or organization that will provide “the right kind of legal and financial home, one that will help the community thrive.” In the meantime, it has announced no plans to discontinue providing security and maintenance updates.

Some observers are hoping that Thunderbird will be picked up by the Document Foundation, which supports Libre Office, the best free office suite of word processor, spreadsheet, and other programs.

Alternately, other free email clients are available to download and experiment with. Among those recommended are:

1. Opera Mail
2. eM Client
3. Inky
4. Claws Mail
5. Mailbird

Postbox, which costs $15, is an email program based on Thunderbird that its developers keep improving.