Use the Services Menu
The Services menu is one of the most underestimated features of Mac OS X. It provides useful commands that work from within almost any application on the Mac without hacking them (unlike, say, contextual menu items which run inside another application's memory space and so can crash it). Both DEVONthink and DEVONagent provide useful commands which allow, e.g., to quickly clip selected text to your database, summarize text, or run a web search. In addition we provide useful Services menu plugins as freeware.