I would like to have a record of all email services, other than Gmail, that have the following feature: a chain of replies to a single original email are placed together into a "thread" so that all subsequent replies are grouped into just one entry in the inbox. It's a format that mimics online forums, where you click a thread title to see the original post and all the replies. Which email services have this capability?
You can use mozilla-thunderbird with any email, and use this extension: https://addons.mozilla.org/en-us/thunderbird/addon/gmail-conversation-view/
You can try Hotmail's Conversation View