Appreciation in Agile teams - "Shout Outs"

Here's a simple idea that provides great benefits for teams. I was working with a team that started giving "shout-outs" at their retrospectives. Any team member could take a minute to recognize other team members for anything they did - whether it was to help someone, take on a task to help out, take on a role even if it's not their primary role.... how do you think this worked out?