[ajays]

Oh come on! In 2005, Facebook was barely out of colleges. Memory's fuzzy, but till about late 2004/early 2005, you could join Facebook only if you had a .EDU address. So expecting Googlers to be Facebook users is a bit disingenuous . Plus, 2005 was over 5 years ago; things have changed since then.

Just because it's an ex-Googler it does not make his (her?) statements the gospel truth.

If there's something to be said, it is that Google underestimated the network effect: that if most of your social circle is on a social network, then you automatically have a large incentive to join it.