Added to the incubator. Thanks!

+1

I like "Letter".

Yes. May single forms installations (like phpBB) has private messages 
integrated in their forums as I guess it was easiest and fastest to 
adopt. But as we experienced, users like much more an dedicated 
interface as is cleaner, more logic and with different functionality 
(ex friends list). And for administration view is a smaller and faster 
api then a forum. And because users send really a lot of private 
messages (much more then post in forms, for us 500 in forums, and 20k 
private) is performance is something important. Yeah, as always ;)
I name it usms as User Short Message System, But we can call it Letter 
-  dictionary: a written message from one person to another.

So, this would be sort of a private message API, to go along with 
Agora for comments/forums?

In any case, seems reasonable to put it in the incubator for now - any 
thoughts on a name?

User interface is like IMP to allow easy user GUI adoption. Does not 
and will never share any code with IMP. Is a internal user messaging 
system intent for communities not for collaboration like mail. You 
don't need any server installation or other administrative tasks. 
Users can send messages to each other without having to share email 
addresses.

There are many communities that have such solutions like mashable.com, 
Drupal has a such module ... My users sends 15 thousands messages daily.

What's the general use case envisioned for this? How much code does it 
share with IMP, if any? Do you see it sharing more in the future?

Screenshoot 3

Screenshoot 2

Screenshoot 1

- interface pretty muck like imp
- attachments
- friend list
- blacklist
- api calls
- php5
- bodies are stored on disk, attributes in sql