Kleiner Perkins partner and early Zynga investor Bing Gordon just tweeted that he’s declaring “‘Zuckerberg’s Law’: [the] quantity of social sharing doubles every 12 months. [The t]rend has held at [Facebook] for 4 years.” Whatever the numbers, it’s absolutely clear that the new social platforms enable breakneck growth. Instagram is growing twice as fast as Foursquare which is growing faster than Twitter did which grew faster than Facebook did. This is because as social platforms grow, the amount of sharing that goes on them grows exponentially, which means new services can be distributed even faster. And you can’t even find Instagram photos on Google: you can find the app’s site, but if you search for a particular user’s Instagram page, you can’t find it on Google. Google was once the overwhelmingly important platform for a startup’s growth, and no it’s not just #2 but utterly irrelevant to the fastest-growing notable startup.