Shared Mailboxes vs Distribution Lists, What's Actually the Difference

I get this question a lot: should this be a shared mailbox or a distribution list? It usually comes up when someone wants a group of people to see the same emails, like info@company.com or support@company.com. The two look similar from the outside, but they behave completely differently once you're actually using them.

A distribution list, or its newer cousin a Microsoft 365 group, is just a forwarding address. Send an email to it, and a copy lands in everyone's own inbox. There's no shared sent folder, no shared calendar tied to the address, and nobody can reply as the list. It's fine for announcements or for reaching a team without knowing everyone's individual address, but it's a bad fit if you want to manage the inbox together.

A shared mailbox is a real mailbox that multiple people open inside Outlook. Everyone sees the same inbox, sent items, and any folders someone sets up. When Sarah replies to a customer from the shared mailbox, Tom can see that reply without her forwarding anything to him. That's the whole point, one shared view and one shared history.

When to use which

If people need to divide up work, track who answered what, or avoid duplicate replies, use a shared mailbox. Support inboxes, general info addresses, and anything customer facing usually belong here.

If you just need to send a message to a group and don't care about shared visibility, a distribution list is lighter and easier to set up. It's also the right call when the members mostly need to be reachable, not collaborative, like an all staff announcements list.

A few things that trip people up

Shared mailboxes don't need their own license as long as they stay under 50 GB, which surprises a lot of people who assume every mailbox costs money. Distribution lists, on the other hand, can get messy if you've locked them down to internal senders only, so check that setting if outside contacts will be emailing in.

One more thing worth knowing, you can convert a regular user mailbox into a shared mailbox, but you can't easily go the other way without losing history. So if there's any chance a shared address might later need its own sign in, it's worth thinking that through before you build it.

Neither one is better across the board. It comes down to whether you want a shared inbox people work out of together, or just an address that fans mail out to a group.