Two tools that look identical from the outside
Your team needs one address customers can write to: contact@, info@, support@. Seen from the sender’s side, a distribution list and a shared mailbox are indistinguishable. The message goes to one address and, with luck, an answer comes back.
Inside the team, the two behave nothing alike. One copies each message to everyone; the other keeps a single copy that everyone opens. Small teams often pick whichever one somebody already knew how to set up, then live with the side effects for years. It is worth understanding what each tool actually does before the habits harden.
What a distribution list really does
A distribution list is a forwarding rule with a friendly name. Whether it is a Google Group used as a mailing list or a Microsoft 365 distribution group, the mechanism is the same: a message sent to the list address is copied into the personal mailbox of every member.
Microsoft is explicit about the intent: distribution groups are for sending email notifications to a group of people, and they fit best when you need to broadcast information one way. That is the design, not an oversight.
The copy-to-everyone mechanic has three consequences.
Replies leave the list. A customer writes to contact@, Sarah answers from her own mailbox, and the customer’s next message lands only there. The rest of the team has lost the thread. If Sarah is away for two weeks, the conversation is frozen in a mailbox nobody else can open.
There is less shared history than it looks. On a Microsoft 365 distribution group there is none at all: a colleague added to the list in September receives messages from September onward, and everything older sits scattered across personal mailboxes. A Google Group can keep past conversations online for new members to browse, but that archive only holds what went through the list address; the replies people sent from their own mailboxes never reached it. Either way, when the newcomer asks what was agreed with a supplier last spring, the honest answer is: nobody knows where that email lives.
And nobody owns anything. Every member received the same copy, so every member can assume someone else is dealing with it. Google concedes the point in its own product: Collaborative Inbox exists precisely to add ownership on top of a plain Google Group, with the ability to take a conversation, assign it to a member and mark it complete. If a bare list gave anyone ownership, that layer would have no reason to exist.
What a shared mailbox changes
A shared mailbox inverts the model: one mailbox, one copy of each message, several people allowed in. In Microsoft 365, this is the standard setup behind info@ and support@ addresses that a whole team watches.
Done properly, it fixes two real problems. History becomes central: everything sent to the address lands in one mailbox, and a newcomer can read last year’s exchanges on day one. One setting to know about: by default, Microsoft 365 saves replies sent as the shared mailbox to the sender’s own Sent Items folder, so an admin has to switch on the sent-items copy for the team’s replies to stay central too. And there is no shared password: Microsoft recommends blocking sign-in on the shared mailbox account itself, so each person gets in through their own account with their own credentials. We cover the setup in detail in our Microsoft 365 shared mailbox guide.
The trap is the improvised version. Plenty of small teams build a “shared mailbox” by opening an ordinary Gmail or Outlook account and passing the password around. Same phrase, very different object: that setup runs on a shared password, with the security exposure and provider lockouts that come with it, and it adds no structure at all.
Even a proper shared mailbox stops short of the essential thing: an owner per message. Five people can open the same mailbox, and the daily question stays unanswered. Who is handling this one? A message someone opened is not a message someone handled. There is no status, no internal note, no reliable way to mark a conversation done beyond folder rituals the team has to invent and police itself.
The gap both tools share: ownership
Picture Monday morning at a three-person shop. A customer asked for a price on Friday evening. On a distribution list, all three got the copy, each assumed a colleague had it, and the customer heard nothing. Or two of them answer ten minutes apart, with two different prices. In a shared mailbox the failure is at least visible: the message sits there, marked read, belonging to no one.
So the interesting comparison is not really list versus mailbox. It is broadcast versus ownership. On the Google side, Collaborative Inbox features are one way to get that ownership; we compared the options in our Google Workspace guide for small teams.
When a distribution list is the right choice
Credit where due: for one-way broadcast to a known group of people, a distribution list is exactly the right tool. Internal announcements to staff@ and automated alerts from a server are the obvious cases. So is a date change sent to thirty volunteers. It costs nothing and needs no training. If nobody is expected to reply, or replies can go to one person without follow-up, use a list and stop thinking about it.
The rule of thumb is the direction of the mail. Information flowing out: a list. Conversations flowing in: something with an owner per message.
When you need an owner per message
The moment customers, parents or members write back and expect an answer, you need what a list does not give and a shared mailbox only half gives. Each conversation needs one owner and a done state. It also needs a place for internal notes, so the team can discuss a message without forwarding it around.
That combination is what a shared inbox adds. With Trupeo, you connect the mailbox you already have (Gmail, Outlook, Microsoft 365 or any IMAP provider) and the team works on top of it: each person keeps their own login, each conversation gets one owner, an open or done status, notes and tags. The centralized history of a shared mailbox, plus the ownership neither classic tool provides.
A short decision guide to close:
- You only push information out: distribution list.
- Several people need to read one archive and replies are rare: shared mailbox.
- Several people answer every day and you need to know who owns what: shared inbox.
If you are starting from scratch, our complete shared inbox guide walks through the whole subject. To see what this looks like in practice, have a look at the features or our pricing.
Sources:
- Compare types of groups in Microsoft 365: Microsoft’s definition of distribution groups as one-way email notification tools, and of shared mailboxes as a common mailbox for several people.
- About shared mailboxes in Microsoft 365: shared mailbox use cases and Microsoft’s recommendation to block sign-in on the shared mailbox account.
- Use a group as a Collaborative Inbox: the take, assign and mark-complete features Google adds on top of a plain group.
- Messages sent from a shared mailbox aren’t saved to the Sent Items folder: the default Sent Items behavior for replies sent as a shared mailbox, and the admin setting that keeps a copy in it.