Ah, I missed that quirk of your proposal. But it would be nice if people could choose to have their sent messages default to not deleted because they prefer to keep a record of them.

Yes it would. And while I was on the "use the message system" track I was thinking we would create a special folder number that permissions checks would use. So the query actually wouldnt be X to Y, but X to Y in folder=N. And all of that is indexed anyway.

Yes, what is vital in technical decisions is an assessment of tye's emotions.

Now now, dont be testy. I didnt use "feel" in the sense of your emotions. You can safely s/feel/think/ or s/feel/believe/ and the intended sense of my statement should remain the same. :-)

You are going to add infrastructure to make it easy to put this information in a place already defined to have a quite different purpose for what reason?

Mostly code/infrastructure reuse. Using the message system IMO would be a minor change. But I'm also ok with doing it an alternate way as you suggested.

BTW, part of the reason I find the idea of using the message system in this way attractive is because its already a place where we have a level of shared data between two users. So to me it makes a certain sense to use it where shared data comes up. But as I already said, if in your assesment it would be better done other ways then I'm ok with that.