I read this this morning in a MocoNews story about the National Basketball Association partnering with Turner Broadcasting System to jointly manage the NBA's domestic digital businesses:
Asked why go in this direction when the NFL, most recently, and MLBAM went in house, NBA Commissioner David Stern said it reflects the way the NBA is doing business today: "We have extraordinary opportunities on a global scale. ... We think we are in an 'era of partnership' ... having your own expertise in every aspect of a business is ultimately going to turn out to be too expensive for us and, ultimately not the best opportunity for growth."
To partner and outsource or to diversify inhouse capabilities - that's one of the big strategic questions companies need to answer in order to cover off their wide range of activities. I'm not sure one model is proving more popular than the other; it seems an even split. Either way though, whether it's the sourcing and balancing involved with partnering or the management of a many various functions, a generalist approach to management is useful.