Having a large portfolio of publishers obviously presents the opportunity to increase margins through dept/function duplication. But you cannot discount the complexity of owning/operating multiple branded publications all needing to remain somewhat unique… otherwise users will smell the lack of authenticity (ie, it will end up feeling like a portal and not the site that user “discovered” and fell in love with).
And thus, when you have multiple properties that can’t be cookie cutter, you not only have the sales and technical issues noted in this PaidContent article, but also, you begin to reduce the amount of duplication (read, margin opportunity) while increasing the HR and other new organizational functions (read, incremental costs). And unfortunately, you also dilute the passion and founder focus (read, sole publisher/founder living and breathing every little traffic source and cost and nickel of yield in order to be able to cover the rent).
Just sayin’… creating one giant brand might be easier. But the holy grail is still to effectively own a bunch.