>> I'm looking for a decentralized instant message system (e.g. XMPP, SIP,
>> ...) where I can be sure that I receive all messages, even if I'm not
>> connected when the message is sent [ Obviously, I'll only receive them
>> when I'm back online. ]
> I believe that's called "electronic mail" or "email".
There's that, and there are SMS messages as well, indeed.
But email is a lot more heavyweight and drowned in spam (e.g. most
people don't get notified right away when they receive an email
message), and SMS is basically limited to cell-phone only (you can find
services that let you send SMS messages from something like a SIP
account, but I haven't found any corresponding service for the
reception of SMS messages, except some that just drop the SMS message
if the SIP delivery cannot be performed because you're not connected).
Stefan
