I wrote about the further balkanization of SMTP-based Internet electronic mail, lamented by the headline article here, some ten years ago in http://homepage.ntlworld.com./jonathan.deboynepollard/FGA/sm... .

I am surprised and encouraged to see IM2000 mentioned in this discussion.

As to whether such ideas have fallen out of favour, I offer this observation:

You are using a pull-style electronic communications system right now. Your WWW browser is the originator and receipient UA, and Hacker News is the message store. A copy of a message is only made and sent across the network when you request it with your User Agent. A lot of Internet-mediated communications are not SMTP-based any more. The shift to pull-style systems has, in some ways, actually already happened.

As such, many of the things that people ask about IM2000 are questions that they can answer from their own direct experiences, with a little reflection. How do you deal with senders who alter their messages? Well: how do you the receipient deal with the fact that right here and now I can hit an edit button and modify this comment after people have pulled it for reading it, with no edit history and nothing but the honour system for dealing with letting people know? The fleshing out of IM2000 set out the idea of downloading to folders in the recipient MUA the messages that one wanted to take off the senders' mail stores, by the way.