Unlike some people, I maintain a good relationship with e-mail. I keep my inbox empty (see Empty your inbox), and junk mail no longer wastes my time, thanks to the combination of Gmail's spam filtering and C-Command's $30 SpamSieve 2.7. Because I'm almost always too busy for microblogging and random chatting, I use Twitter only occasionally and instant messaging even less. Nevertheless, I've discovered that in certain situations, Twitter is a better way to communicate than e-mail.
1. When avoiding junk-mail filters is a priority
Twitter doesn't include--or need--anything like the spam filtering that's de rigueur for e-mail, because it's inherently an opt-in system. You follow only those people you want to read about, and you can "unfollow" people at any time if you don't want to read any more of their tweets. You can also block people who follow you if you don't want them to receive your tweets (although they can still view your public page on the Twitter Web site). This makes it quite easy to avoid junk tweets, however you define them. As a result, if you want to be positive that someone gets a message from you and that it won't be inadvertently swallowed by his or her spam filter (as has happened to me several times recently, when sending completely innocuous e-mail messages to colleagues), a direct-message tweet may be just the ticket.
To send a direct message, start a tweet with a D followed by a space and the username (as in D joekissell). This is different from simply replying to a tweet by putting another person's Twitter username, preceded immediately by an @ sign (as in @joekissell) at the beginning of a tweet. When you reply normally, everyone who follows both you and the other person will see what you wrote--and so will the person whose username you typed, whether they follow you or not. In addition, your tweet will show up in your public feed. By contrast, when you send a direct message to another user, only that person will see it (and not anyone who follows either of you). The trick is, you can send a direct message only to someone who follows you, so for two-way direct messages, you and the other person must be following each other. So, for example, if you follow me and try to send me a direct message but I don't also follow you, the message won't go through.
Likewise, if you know that your correspondent suffers from an overflowing e-mail inbox, a direct message can ensure that your communication stands out from the crowd. In any case, one catch is that you must be confident that the other person checks Twitter regularly. If they tweet frequently, that's pretty much a given. But also make sure the other person knows how and where to look for direct messages, because some Twitter clients (especially on the iPhone) make them easy to miss.
2. When you need a handy universal contact page
Another situation in which Twitter shines is when you don't want to give out your personal e-mail address. Your Twitter page is public--anyone can search for your name and also see what you write, unless you specifically protect your account. This means you can refer all those random people who run into you at conventions or who stumble on your Web page to your Twitter page as a contact method. The result will be that they can't contact you privately unless you also agree to follow them; this can significantly decrease the incidence of unwanted messages!
3. When you want to tell friends about the newest dancing baby video
Direct messages aren't the only way in which Twitter can substitute for e-mail. If you like to forward to your friends the URLs for interesting Web sites, funny pictures of your pets, or other such non-sensitive subject matter, you can probably distribute the same information more quickly and easily in a tweet. Although you won't be able to control who sees the information, that fact may be an advantage in that the interesting, funny, or otherwise noteworthy content is disseminated further. You'll also reduce the amount of mail in your inbox because each recipient won't feel obligated to reply!
4. When your group needs a fast way to share
Twitter may also be a good alternative to mailing lists for small groups that need to share critical information with each other in real time and don't want to risk e-mail delays or outages. For example, the staff of TidBits has a special, protected Twitter account (that is, one whose tweets are visible only to people explicitly allowed by the account owner). All the staff members follow and are followed by that account, so if one of us needs to alert the rest of the staff to something in a hurry, we can simply type a quick direct message rather than send an e-mail message.
Senior Contributor Joe Kissell is the senior editor of TidBits and author of numerous e-books about OS X.
This story, "When to Use Twitter Instead of E-mail" was originally published by Macworld.