Does DEVONthink come with the ability to monitor a folder and if it sees any activity in that folder (say, a new file) to automatically import it? Or, would this be something I would have to make in Automator?
Yes. The DEVONthink application download disk image contains a folder named Extras, and within that folder there are two Folder Action scripts that can be copied to your computer (one to Import, one to Index new content). Now you can, for example, attach the script that will Import new content added to a Finder folder, and that content will now be sent to your database. There are directions in the Finder’s Help menu on how to do this, as well as in the DEVONthink Pro/Office Help menu.
Remember also that, if you use DT Pro or DT Office 2.0, you can directly Save or Save As new content from almost any application to your Global Inbox by choosing the ‘Inbox’ Place in the left column of a Finder navigation panel. If the Inbox location isn’t already there on your computer, just locate the Inbox folder at ~/Home/Library/Application Support/DEVONthink Pro 2/ and drag it into the ‘PLACES’ group of a Finder window.