Last week, I covered Herald, which lets you monitor your incoming e-mail when Mail is hidden. But I’m also a big fan of software that helps you get more out of Mail itself. MailHub is just such an add-on.

MailHub is a Mail plug-in that adds a new toolbar to the top of Mail’s message list, just below the main toolbar. (You can hide and show the MailHub toolbar as desired.) This toolbar provides a number of useful new features. The first is a new mailbox-Search field: To switch to a different mailbox view, click in the field (or press a configurable keyboard shortcut to focus on this field) and type the first few letters of the mailbox name; once you’ve found the desired mailbox, press Return to view it. (Unfortunately, this feature doesn’t work for Smart Mailboxes.)

You can also use this field to create a new mailbox: Just type the desired name of the new mailbox and press Return. MailHub will ask you where you want the mailbox created (on your Mac or on an IMAP account's server) and then create it. Finally, the search field also makes it easy to file messages: Just select one or more messages, use the search field to find the desired mailbox, and then click the File button. (Hold down Shift, and File changes to Copy—MailHub places a copy of the message in the designated mailbox, leaving the original message in place.)

But you don't have to type a mailbox name every time you want to file a message. After you’ve been using MailHub for a while, it learns your filing habits and preemptively suggests mailboxes for filing selected messages. It does this by first—on initial installation—indexing your mailboxes to get an idea of how you’ve filed past messages; then it watches how you file messages going forward. These suggestions aren't always perfect, but during my testing I found that MailHub often correctly predicted where I was planning to file a message, displaying that mailbox in the Search field—a quick click of the File button moved the message exactly where I wanted. And the more you file mail using MailHub, the more accurate its predictions become.

The File button has a few extra features of its own. If you hold the mouse cursor over the File button, you’ll see options to File Thread and File Sender. The former files all messages in the same thread as the selected message; the latter files all messages with the same sender as the selected message. Wondering what, exactly, will be filed? Click-hold the mouse cursor on the Thread or Sender button, and MailHub filters the current mailbox to display only the messages that option would file. (Click the Home button to restore the view to display all messages.) When filing messages, a confirmation notice appears briefly on the screen to let you know how many messages were filed.

The Delete button works much like the File button. A single click deletes the selected message(s), but you also get options for deleting all messages in the same thread as the selected message, and for deleting all messages with the same sender as the selected message. As with File, you can click-hold on the Thread or Sender buttons to preview exactly which message(s) will be deleted. MailHub will also warn you if you try to delete (or file) too many messages; you configure the warning threshold in MailHub’s settings.

The other major toolbar feature is Remind. Select a message and click this button, and MailHub will let you schedule an iCal/Mail To Do with the selected message pasted into the task's Notes field. This is a handy way to ensure you follow up on a message.

MailHub offers a slew of other options you can configure via its settings screen. For example, MailHub can automatically file each reply you send into the same mailbox as the original message. (If you choose this option, a related option can tweak your mailboxes to display a combined To/From field that automatically displays the most useful information for each message—the sender's address for messages you receive, and the recipient's address for messages you send.) You can also choose to hide particular mailboxes from MailHub, or just exclude them from MailHub’s filing suggestions, and you can configure keyboard shortcuts for most of MailHub’s features.

I found MailHub’s general sequence of actions—selecting a mailbox and then choosing the action to perform—to be initially counterintuitive, but I got used to it after a few days of use. And as an inveterate message-filer, there’s no question that I was able to more quickly manage large amounts of e-mail with MailHub installed.

(Keep in mind that because Apple doesn’t officially support Mail plug-ins such as MailHub, there’s a good chance that the next time the company releases an update to Mail, any third-party plug-ins you have installed will stop working. If that happens, you’ll have to wait for the developer of each plug-in to release a new version compatible with the updated version of Mail.)

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