Google applications serve a utilitarian mandate: they encourage users to search for something, consume, and move onto the next thing. Google apps are for working and getting things done; social apps are for interacting and having fun.
Googlers who wanted to develop great social applications had to leave Google to do so. Google has an environment that viewed social networking as a frivolous form of entertainment rather than a real utility, and I’m pretty sure this viewpoint was shared all the way up the chain of command to the founders.
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