Is there a shortcut to make a private line that isn't really private?  Something like:
(And pretend that the angled brackets are parentheses.)
<Private to Everyone: Yes, it is secret, don't mention it. :)>

If all recipients are left off the private line, can only the GM see it?  Like:
(And pretend that the angled brackets are parentheses.)
<Private to : This is a private message! Stop reading it! ;)>

When I want to leave myself a note in a game I run -  I just address a private Note to the GM - me!  I use them to keep track of monster stats, treasure lists, locations of invisible or stealthy opponents  and all sorts of other things.

If I wanted a private a line that went to everybody -  I think I would just set up a language group call Common and add everyone to it.  :)  Although personally, I tend to write that in the post itself or as an OOC.

If you want them to each think they each know a secret that the others don't -  you need place a private line for each character -  but Copy and Paste is your friend  :)
This message was last edited by the user at 07:09, Wed 30 May 2018.

In reply to Genghis the Hutt (msg # 1):

Additionally, a private line sent to nobody will throw an error when you try to post it.

EDIT:
If the private line is sent as "Private to Nobody" in a game, it gets routed to the GM instead.  It's notable that I cannot even include an example of this surrounded by code tags in a public forum without throwing an error.  It makes me wonder what would happen if I named a character in a game "Nobody".

If the private line does not include a recipient:

[Private to:  this should be visible by all.]
END EDIT

You can send private lines to NPCs, but I don't know the long-range effects if that NPC is transferred to a player's control for any reason..

As JohnB pointed out by implication, tagging everyone's checkbox on a private line will make it so everyone can see it, but also show them the recipients list...

What were you trying to accomplish?  There may be a better way than using a pseudo-private line.
This message was last edited by the user at 13:35, Wed 30 May 2018.

A private line can be sent to nobody simply by setting up a language group with no members (I call mine "No players").  Even without any members, you can still send PMs to the group, and only the GM can ever see them.

In reply to bigbadron (msg # 4):

I've done some experimentation in one of my "games" designed for that purpose.  The results may interest you.  There are some things that are still not conclusive (I may have made some errors, so I repeated some steps and could not reproduce some earlier results.)

I'm already aware of the results I've been getting, using the method described above.  It's how I put secret GM notes in my games, and has been since private groups became available.

You just have to remember to use "Private to group... " and not "The language group... " (which will post a garbled message for everybody except you).  "Private to group... " has the advantage of posting the text in a different colour (like any other private line), so it stands out when you're skimming through the thread.

In reply to bigbadron (msg # 6):

That's actually a neat feature.  Thanks!

If "Nobody" is a valid character name in the game, then private lines can be sent to them just like everybody else.  The error's arise when you try to address a private line to a non-existent character.

I occasionally have tried setting up "Utility" Characters like Mapping, Equipment, and Treasures.  simply to keep all sets subjects in one "place".

I'm in the habit of posting OOC lines within an in-character thread

[this way]

specifically because it mimics the way private lines appear. :\