I am trying to send an email as a reply to a previous thread using SendGrid v3 APIs. But it always shows as a new email thread in Outlook. I am using "Message-ID", "In-Reply-To"...

I'm trying to work out how best to connect / thread a chain of emails. This seems like such a common problem that I was surprised that I couldn't easily locate information on how other people have ...

I've read some great online resources like http://www.jwz.org/doc/threading.html, and it seems that any email is send with a Message-ID header, then any replies to it include In-Reply-To naming tha...

Everyone knows, if you want to thread emails you use Jamie Zawinski's algorithm. But it's a new century, and there's a new messaging service. What's the best algorithm for threading status updates...

Are there any named/famous/particularly good algorithms for organizing email messages into threads? I'm looking to add a feature to my site similar to Google Groups (and other mailing lists) and I...