OK, how about highlighting some error message in a log file, right clicking and choosing a menu option that googles for the string (filtering out dates, times, host/domain names and perhaps some filenames too) then opens a browser window with a tab for each SO answer? Now _that_ is definitely part of my debug workflow. Not sure its the next killer app though. Actually, I could probably knock it up in half an hour with AppleScript and Automator on OSX, as a new 'Services' menu item...?!
I fiddled with Intellij plugins; seems like it would be pretty easy to write if you've written one before, maybe a weekend project if you have passing knowledge.
I'd give myself a week, including the time to search Stack Overflow :)
