Can we configure Appian to automatically send an e-mail notification when we pos

Not OOTB, I don't believe. A few options here would be:

1) Create a process model ('Action') to post, which both creates a news event and then sends a message.
2) Connect to the primary DS, check periodically for new posts and send messages accordingly.

Note, in #2, creating a business datasource connection to the primary DS is not supported.

Option #2 is not an option in the cloud either.

Create a group called "All Users". Add that group to all Tempo posts when the post is made.

We already put a group as a participant on the News item. Does not work. I thought that addressing the News item to a single user would work but it doesn't.

Should add that this is when we post to the news feed using the smart service.

Paul, are you referring to adding the group to 'Viewers' or 'Participants' of the post? In my experience, the only way to automatically receive an email notification on a post or updates is to have physically comment on it - or if a single user is set as the 'User' in 'Post Event to Feed' node (vs System Event), they will receive a notification, but the post will be attributed to them.

Also, being a participant on a news entry does not warrant a notification either. Based on the notification scenarios, it would be great if we could do something such as programmatically 'star' posts for users to force notifications - I had thought I submitted an enhancement for this but cannot locate it at this time..

forum.appian.com/.../Notifications.html

adding to participants. If you add someone they get an email that says "A group you belong to was added as a participant to a news entry from ________"

I realize this may not be turned on by default.

On your appian site go to /suite/apps.
Click alerts in top right.
Click "edit my alert settings".
click feeds.
click "Group has been added as a particpant"
By default, send to email with parameters timing = immediate.

Ah yes, that would generate a single notification at the time they were added - sounds like that may work for the OP here. My original use case was to have users receive messages after comments, when they have not physically commented or starred the post. forum.appian.com/.../e-171528