I was attending a session at the Agile 2011 conference where Jean Tabaka from Rally Software was talking about some generic agile coaching tools & techniques. Jean happened to mention a few times that Rally had been internally focused on some organizational change models that happened to focus on strengths, positive recognition, and appreciations.
Focusing in on appreciations, she stated that it started in team retrospectives. That Scrum Masters would ask the teams to share their appreciations of each other as a start-up or entry ceremony for each retrospective. But then it caught onto other organizational meetings. She mentioned that many of their company-wide, all hands meetings began with appreciations.