Live streaming startup Ustream powered a webcast last week for Disney pop trio The Jonas Brothers. Now the company has revealed that 974,000 people watched the webcast at some point.What’s more, it integrated with viewers’ Facebook and Twitter accounts to help promote the event – they made 1.5 million Facebook posts and 40,000 tweets during the webcast.The Jonas Brothers (or rather the people who run their digital affairs) have been pretty forward thinking when it comes to online video. Last June, they worked with online video firm Kyte, posting regular footage of their on-tour exploits to their Bebo profile.