Mail Act-On 2 also makes it much simpler to configure rules. Under older versions, because Mail had only a single list of rules, you had to name Mail Act-On rules using a very specific format to differentiate them from standard rules (and to indicate the keystrokes for invoking them). In version 2, Mail Act-On actually modifies the Rules screen in Mail's Preferences dialog, dividing it into Inbox Rules (Mail's standard rules), Outbox Rules, and Keystroke Rules; the dialog for each Keystroke Rule now provides a field for choosing its keystroke.

(Tip: If you regularly need to perform several actions on the same message[s], but you can't include all those actions in a single rule--or if you want the message[s] to be compared against several distinct sets of criteria--you can create multiple keystroke rules and assign them to the same keystroke. When you press that keystroke, Mail Act-On will apply all those rules to the message[s].)

My personal favorite among Mail Act-On 2's new features is the ability to quickly move messages to a particular folder, even if you haven't defined a rule for this task. Much like , Mail Act-On lets you press a keyboard shortcut (by default, F3) and then type the first few letters of the desired folder name. Assuming those letters are enough to identify the desired folder, you simply press return to move the selected message(s) to that folder; if more than one folder matches, you can type more letters to narrow down the choices, or you can use the arrow keys to choose the folder manually. If you've got lots of subfolders, Mail Act-On provides several shortcuts for quickly navigating your folder hierarchy. Similarly, you can press option-F3 (by default) to copy selected messages to a folder.

For both the move and copy features, the most-recent folders are displayed at the top of the list for easy access, each with a numeric keyboard shortcut; for example, 1 for the most-recently-accessed folder. When reading your email, there's also a feature (shift+F3, by default) for quickly switching to a different folder.

If you'd rather not have to remember these various menu shortcuts, you can instead use Mail Act-On's main menu, accessible by pressing F1, which gives you quick access to all feature-specific menus.