I use a lot of those in my work mail: - open in different window: all the time. I am writing one email and searching/reading email archive for context. Also ju

I use a lot of those in my work mail: - open in different window: all the time. I am writing one email and searching/reading email archive for context. Also just keeping an individual message open in a separate window as a reference, while using main email window regularly. - greetings line: I don't think it's a "feature" but I use it when starting a thread, especially when writing to people who I am not very familiar with. - quoting entire mail: pretty frequent, for example when adding a new person to an email thread. Also handy for selective reply, it is easier to delete parts you don't need from quoted email than to start from blank and copy from original email. - inline/attachment toggle: I don't think my email program has this - threads split across mailboxes: not very helpful. But the multiple mailboxes is must-have. - clickable message list: situational but occasionally helpful. Mostly when the is a thread with lots of messages, and you are looking for this rare message from the specific author. - custom signature: I am don't have one personally, but some people put their position, office location and phone number there, and this is pretty helpful. The email is different than instant messaging - it is harder to use, but is much more powerful if you learn to master it. The deltachat (judging by screenshots on their website) seems like a very basic and low-featured client, which unfortunately promotes bad habits in email, like writing short messages and expecting instant replies. I am glad it has not caught on.