(and I also think PicoTorrent will get more downloads because it's easier to Google for)
Such as thunderbird, icedove, mutt, gnus, mew, outlook, outlook express, etc?
Gmail, Hotmail, Yahoo Mail are email services first and foremost. Most native clients do not have mail in the name.
Yes, but mail isn't the same as SMTP or IMAP or POP.
In public communication, it almost never helps to start a sentence with "well, technically".
The name told you what you could expect the technology to do. That's why it made sense to include these words in the name of email clients.
The same is not true for "Matrix".
Chat seems to be closest?
So MatrixChat might work?
Genuinely asking.
Well, that's only sensible—you're not sending an SMTP message. SMTP isn't a message format. It's a wire protocol for passing along pre-formatted messages. What you're sending is a MIME message, over SMTP. (Just like you send HTML over HTTP.)
The distinction is even clearer in the email case, actually, because those same MIME messages also show up in other transfer protocols (POP, IMAP.)
There are actually a few email clients that use "MIME" in their names. But it's pretty rare.
Conveniently, though, "MIME" is short for "Multipurpose Internet Mail Extensions", so "Mail" is actually in the name. ;)
Those get named after the overall framework (if they're not just named "fooVPN" or simply "foo") even though there's no single IPSec protocol, and many many different underlying protocols.
I mean I don't think the browser analogy is that great, it seems more the exception than the rule. Eg most IRC clients have the word IRC in them, or something very close (eg mIRC, irssi, etc). Most email clients have the word "mail" in them. Torrent clients, same. Why shouldn't a Matrix client have the word Matrix in it?
Just call it iMatrix or uMatrix or something like that, and you're removing a lot of confusion. If mIRC and uTorrent and Gmail can get away with that, so can you.