Baseball has reaped a windfall from MLBAM: its $800m in revenue last year was 9% of the major leagues’ total. Its growth could accelerate as streaming video gains ground. Last month Twitter said it had acquired Periscope, which lets users share live footage from their phones. Businesses built on such “social streaming” could create a new category of customers. Although MLBAM is sure to attract competition, it enjoys strong barriers to entry. Since reliability is paramount in live video, content owners are willing to pay up for a provider with a proven record. And only a well-heeled rival could replicate its network of data centres—its capital spending has already exceeded $500m.