Can I use Alfred, Launchbar, Hazel, etc. with DEVONthink?

It really depends on what you're hoping to do. DEVONthink has powerful automation capabilities allowing it to interact with many other applications on your Mac, especially AppleScript-aware ones. Hazel and Keyboard Maestro are two such applications that many of our customers have integrated with DEVONthink. A web search or a search of our community will often turn up some great ideas!