Saving a message saves it for only you.
Pinning a message flags it for an entire channel.
Save messages for later follow up by selecting the Save icon next to a message.
To see all of your saved messages, select the Bookmark icon to the left of your avatar. The right-hand sidebar opens to show the list of saved messages.
All members of a channel can pin important or useful messages to that channel. The list of pinned messages is visible to all channel members. There is no limit to the number of pinned posts in a channel.
Mouse over the message that you want to pin. The […] link appears.
Select […] > Pin to channel
Pinned messages are marked with the pinned icon. For example:
To see all pinned messages in a channel, select the Pin icon located in the channel header.
The right-hand sidebar opens to show the list of pinned messages. For example: