Google did something really similar with their gchat launch on Orkut. They started out with just 1% of the userbase running it in the background and scaled it u

Google did something really similar with their gchat launch on Orkut. They started out with just 1% of the userbase running it in the background and scaled it up from there till they were confident that the implementation details were mostly worked out. Its really a great idea for testing the scalability of new features without completely breaking the production site.