These days, much of the reputation management conversation revolves around social media, especially Facebook, Twitter, LinkedIn, and Google+. Email etiquette, like email itself, often gets lost in the inbox. Email, however, remains popular. In fact, according to an Ipsos study reported by Mashable, more people use the Internet for email than for social media. Email has been around long enough that it has its own etiquette. Among the most consistent rules is to respond promptly, even just to say that you will reply in a couple hours. Rapid email response makes you appear courteous and, more importantly, on top of stuff.

The trouble with rapid response is that your clients will expect a reply in a couple of hours. If you don’t follow up, you just shot yourself in the foot. If you’re speedily responding to 10 or 20 emails, chances are you’re going to forget about some of those promises. You could put it all on your to do list, but do you really want to clutter that list with “follow up on so-and-so’s email”? And do you really want to spend the extra half a minute to write out that Google task? How will you balance your reputation management with your time management? I call this the Rapid Response Dilemma.

Luckily, the Rapid Response Dilemma has a simple, free solution. If reputation and time management had a love child, it’d be Boomerang, a new email and calendar tool from Baydin, the guys who brought you the Email Game. Boomerang is a free Gmail plugin for Firefox and Chrome (there’s an Outlook version, too) that allows you to schedule email to be sent later as well as schedule email to be resent to your inbox later. I learned of Boomerang from a Lifehacker interview with the founders of Rap Genius about what apps they can’t live without. Boomerang was at the top of Tom Lehman‘s list.

Boomerang is easy to use and even easier to install. If you use Gmail, simply go to the Boomerang website, and click on the giant red “Install Boomerang” button. Then check your Gmail. There, you’ll get a streamlined Boomerang tutorial. There you go! Boomerang is ready.

Below is a screenshot of me emailing someone about the article you’re reading now. I schedule that email to be sent five days after I wrote it.

Boomerang sent screenshot

Boomerang sent screenshot

Rescheduling an email to be resent to your inbox is just as simple. Below, I reschedule an email conversation to reappear in my inbox sometime in the year 2161, which happens to be the year when the United Federation of Planets will be founded. It’s like a digital time capsule.  Who said time travel isn’t possible?

Boomerang resend screenshot

Boomerang resend screenshot

So how does Boomerang solve the Rapid Response Dilemma? Imagine you get an email from a client, and you can’t answer it just yet. Simply respond to the email with, “Got your email. Busy now, but I will follow up in a couple of hours.” Then Boomerang the email to your self, two hours into the future. Two hours later, the email and a note from Boomerang that you Boomeranged yourself will show up in your inbox. The beauty of Boomerang is that, because Boomerang sends you both the email and a notification that it was resent, you know which conversations are new and which are Boomeranged. Boomerang behaves like a personal assistant whom you don’t have to pay.

You might be thinking, “This is useless. When I’m unable to respond to email, I’m not at my desktop or notebook, I’m standing on a crowded bus or something.” Lucky for you, Baydin just released a mobile version of Boomerang for iOS, Android, and Blackberry. If you take a break from your bus commute Facebook binge to check your email and find an important message that needs to be addressed at your desk, just Boomerang it.

Boomerang is like the screwdriver and hammer of email-driven reputation management. You can use it for a lot more than following up on rapid responses. If your social network is international (or if you’ve got a weird sleep schedule), you can use Boomerang to email people when they’ll be awake. If you know somebody’s work schedule, you can save an email for when the person is most likely to read it. Not only are you more likely to get to the top of their stack, you’ll communicate that you value their time as well as your own. You can also use Boomerang to draft holiday or birthday greetings whenever your have the time, but deliver your message on the day in question. In sum, email scheduling gives people the impression that you have a mind like a steel trap.

Boomerang isn’t the only email scheduler in town. More comprehensive email scheduling services exist, such as LetterMeLater. There’s also Time Cave, which has existed since 2000. Boomerang’s advantage over these tools are that it is plugs directly into the Gmail interface, and it is very easy to use. One disadvantage is that, unlike LetterMeLater, Boomerang doesn’t really do all that much. Then again, that’s part of its charm. And unlike Time Cave, Boomerang hasn’t been around all that long. How reliable is it? I honestly can’t tell you yet with much confidence.

More broadly, what are the implications of Boomerang and similar tools for the future evolution of email etiquette and its impact on your reputation? Boomerang helps to solve the Rapid Response Dilemma, but it could also help you put things off. Just like the snooze button on your alarm sets you up for snooze chains, Boomerang might set you up for Boomerang chains if you aren’t careful. Rather than using Boomerang to manage your time, you might end up using it to procrastinate. To avoid Boomerang chains, take the same advice that experts give for avoiding snooze chains: give yourself more time. Just like a nine minute nap isn’t enough to make you feel more rested, an hour until follow up might not be enough time. So if you Boomerang, Boomerang wisely.