In apple's Mail.app program, is there a way to file messages into a given folder (in my case, my catch-all "archive" folder) using a single keystroke? There is on Thunderbird (I just type the letter "a" while in my message list view, and it's done).
On Mac mail, the native way seems to be only by dragging and dropping. I installed "Mail Act-on", which adds keyboard shortcuts, but there's still 2 keys (an F-key and then another key). That's even suckier for me b/c on a mac laptop, using the Function keys requires a double keystroke (fn + F-key) so it turns out to be a 3 keystroke thing.
I'd be willing to accept a keyboard shortcut that involved a control key (e.g. Command + a), if it was easily reached, but the only one available by default is the "move to X again", which requires remembering the last place you moved something, and doesn't work well for a multi-account setup. I'd love the ability for it to automatically move messages to the right archive folder depending on account (work vs personal) - i.e. a single key ("a") moves work messages into the work archive and personal messages into the personal archive.
(I know this might seem stupid or overly specific, but for something I do hundreds of times a day, that makes a big difference over time; Thunderbird can do it, I've come to expect it.)
With Mail Act-On you can use the control key in conduction with the Act-On key. So it the rule has the A keystroke, ctrl-A will run the rule
Answered by Scott Morrison on August 24, 2010.
I use Mail Act-on as well and get through my email very quickly.
If you're keyboard-centric (as I guess, I see you've answered a question about emacs), you'll definitely want to toggle how the F-keys work on your macbook.
Go to the Keyboard settings and check the box that says "Use all F1, F2, etc. keys as standard function keys". The F-keys will then work without holding down Fn. If you want to increase the sound volume or access other mac F-key functions, you can hold down Fn.
I know this doesn't get you to one key email filing, but I think this will make a big difference.

Update: Intrigued by the idea of single key shortcuts, I looked at Mail Act-On's discussion forums and found a similar request. The bad news is that InDev support says it's not possible, but the good news is that they suggest locking the rule window in place by hitting F2 twice. After locking it in place, a single keystroke will work. So instead of 2N key strokes to file N messages, it's N+1.
p.s. I also recommend enabling tab to move among all controls, not just text boxes and lists. See the setting on the "Keyboard Shortcuts" pane of the Keyboard settings.
Answered by Doug Harris on August 23, 2010. Last Edited on August 23, 2010.
Content from Superuser of Stack Exchange. Original article at Superuser.
Aha - that's exactly what I needed, Scott. I've created two rules, both assigned to the letter "a", and hitting control a moves the messages to the right destination, based on whichever rule(s) apply to the message. That's quicker than F-key followed by a number, though that's also a good way. - on August 25, 2010