The 'v' keyboard shortcut key will bring up a panel which you can use to quickly move the currently selected messages into a folder. Just start typing a folder name and Postbox will show you a list of folders that match.
When you bring up Quick Move a second time, it will default to the last folder used.
Notes
- Folders on the current account will always be listed first before matching folders on other accounts.
- The currently selected folder will not appear as you can't move a message to the same folder.
- If you attempt to Quick Move a message that can't be moved (such as a newsgroup message), a copy of the message will be put in the destination folder.