Either people don't know what reply all is, or social networks have convinced them that broadcasting is the only legitimate form of communication. The handy tool is used so much that the thinking seems to be, "Why tell one person 'thx' when you could deliver that message to dozens of people simultaneously?"
Well, I can think of two reasons: First, replying all at the wrong time can be rude because the sender may not have wanted all responses to be visible to everyone. Second, it's pretty boring to spend the whole day deleting monosyllabic responses to something that never even applied to you in the first place.
This is not to say that there is never a time when "reply all" should be used -- it's just that time is not all the time.
There are a few basic ground rules for when to use reply all. In general, if your response will cause other people to do something different then yes, reply all. If your response will have absolutely no effect on other people and is "thanks" or "ok" then no, don't reply all. In personal communication, reply all should be used for group invites with 10 or fewer people and on discussion threads where at least 70 percent of recipients are actively participating. At work, reply all should be used when you have something valuable to add to the conversation or when you disagree with whatever is being proposed. In general, agreement with a work email is assumed, so an email saying you agree doesn't really need to be a reply at all.
Pro Tip: If you use Gmail, you can use the mute button to silence redundant replies from people who haven't mastered the art of when not to reply all. If you no longer want to see new replies to a thread just click on the message, then click "Mute" under the "More options" button in the Gmail tool bar. Incoming messages on this thread will still be archived with the conversation but will not show up as a new message. If you want to find these conversations later just search for "is:muted."
Read through the following scenarios to see when to "reply one" and when to reply all.
Scenario: A colleague got a new job and sends a farewell email to the whole office. Do you reply all?
No.There is no conceivable reason why anyone but the person who is leaving would want to see your response, since the only person it has anything to do with is the person who is leaving.
Scenario: Your friend invites you and five friends to dinner on Friday. Do you reply all?
Yes. Help out your nice friend who is trying to organize a get-together with you and the rest of your group by responding publicly -- it'll help people to coordinate and is likely to solicit RSVPs more quickly. If I don't see that other people have responded to an email invite, I tend to either forget about the invitation altogether or just take my sweet time RSVP'ing because that's what it looks like everyone else is doing. Replying all is a good way to remind people that their presence continues to be requested at this fun event you are trying to help them have fun at.
Scenario: Your friend invites you to his huge 30th birthday party. Reply all?
Yes, you should go. No, do not reply all. Your presence at a huge party is completely inconsequential to everyone except the host. Reply singular on this one.
Scenario: You're Bcc'd. Reply all?
No. Why? You can't. The Bcc'd are second class citizens not trusted with the ability to reply all.
Scenario: You receive a work email containing a rhetorical question or straight up statement to which the only conceivable response is "ok."
Please no. Your silence here is your assent in this scenario, even though your assent isn't even required since no one is honestly asking you whether this is okay. Stay quiet.
Scenario: Someone sends a company-wide email asking for nominations for the city's best make out bar. Reply all with your recommendation?
Yes. Email threads exist because when they're fun they're fun, but only participate if you have something meaningful to add. It's your call on whether what you want to write is meaningful, but a good general rule is if you have to sit there racking your brain for a clever response, you shouldn't be replying to that thread. Save your replies for conversations that really speak to you. Reply all is like anything else: with every use it decreases in value.
Scenario: You're on an email thread that no longer applies to 70 percent of the recipients because they're not going to dinner, participating in the blood drive or hoping to make out with someone they work with. Reply all?
No. Have a heart and remove the non-responders from the list. Remember, it's only by removing the dead leaves that you allow the bush to flourish.
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