There is I think a difference in company culture. Sure, it is not something you can measure like market capitalization or dividends, but that doesn't make it insignificant.
It is common for people to say that all big companies are equivalent in that they just look for the best strategy to maximize shareholder value, which they have to do by law. I don't think that's the complete picture: there are humans behind every company, behind every decision they make. If Larry Page and Sergey Brin believe in an open Internet, that will strongly influence what strategy among many they choose to maximize shareholder value. Well, as long as they have a controlling stake, which might be for a long time seeing the recently announced stock split.
But it's not only board members who determine how open a company is. For example, developers have their say in what technology or protocol will be used for a particular project. What they propose might depend on their personal views, and what passes as a valid argument (e.g. openness or standard compliance) depends on company culture. Personal views and company culture obviously depend on who gets hired, and that's a matter where anyone (developer, HR, etc.) might have a say. If Google employees have a bias towards hiring people who embrace open technologies, that will have an effect. And if Google's image tends to attract job applications from people who believe in an open Internet, that will also have an effect. This culture thing is probably more stable than a strategic position.
