Here's what Google had to say last year about exporting emails from their social network, Orkut:<p>"Mass exportation of email is not standard on most social networks — when a user friends someone they don’t then expect that person to be easily able to send that contact information to a third party along with hundreds of other addresses with just one click. In order to protect user privacy, we now exclude email addresses from the CSV export file."<p><a href="http://techcrunch.com/2009/10/26/orkut-slows-hemorraging-to-facebook-by-making-friend-export-tool-nearly-useless/" rel="nofollow">http://techcrunch.com/2009/10/26/orkut-slows-hemorraging-to-...</a><p>This is almost exactly what Facebook says today, while Google PR fakes a stroke in front of every blogger who'll pay attention. What was different was that, in 2009, Orkut was still the network of choice in two important markets (India and Brazil); "openness" of the sort that Google is advocating for its competitors would have actually been expensive.
In a wide variety of circumstances the right law is n * log(n). See <a href="http://spectrum.ieee.org/computing/networks/metcalfes-law-is-wrong" rel="nofollow">http://spectrum.ieee.org/computing/networks/metcalfes-law-is...</a> for an explanation.
<i>"Google might very well genuinely believe in openness. But it is also strategically wise for them to be open in layers that are not strategic (mobile OS, social graph, Google docs) while remaining closed in layers that are strategic (search ranking algorithm, virtually all of their advertising services)."</i><p>I don't think can call Google "open" or "closed" in the sense of interoperability with respect to page rank. No one else puts information into pagerank. Google's search software isn't open source but that's a different question than social-network/email interoperability.