Thanks for the example. Looks like good stuff! I've posted a link to it on the Spring Social home page under Buzz.
One thing I found interesting in your article is that you do your OAuth dance with Facebook on the server-side. There's nothing wrong with that and it's nice to see an example of how to do that. For Greenhouse, however, I found that it was easy enough to use Facebook's <fb:login> XFBML tag to prompt the user to authorize the application. Then in a Spring MVC controller I can use Spring Social's @FacebookAccessToken annotation to pull the access token out of the cookie that was written after authorization.
Either way, though, your article is good stuff. Thanks for spreading the word on Spring Social.
Spring Social Project Lead