On my MacBook Pro I have found that several applications seem to share the value for a find. For example, I searched 'applestackexchange' in Safari's unified address bar, then I switch to Xcode and click into a Find field. The first word of my search in Safari then appears there. iTerm2 and Sublime Text 2 also seem to participate in this sharing.
Running latest Mountain Lion on a 2012 MBP.