So says this Bloomberg article: http://www.bloomberg.com/news/2012-05-07/zuckerberg-stock-grip-becomes-new-normal-in-silicon-valley-tech.html

It used to be uncommon to have very little Board oversight.

Now it is quite common:

Companies that have three or fewer outside board members include Pinterest, an online bulletin board; Dropbox, a provider of Web-based storage; question-and-answer site Quora Inc.; Flipboard Inc., the maker of a magazine-like application for the iPad; and Nest Labs, the creator of a technology-powered thermostat. Zuckerberg adopted a dual-class structure in 2009. He has 10 votes for every other shareholder’s single ballot.

“People look at Facebook and see what they have done,” said Stephen Venuto, a partner at Orrick, Herrington & Sutcliffe LLP in Menlo Park, who helped Facebook set up its initial corporate-governance structure. “It’s become a much more common thing to implement dual-class capital structures in Silicon Valley companies.”

It's eye opening to see how Groupon and Zynga behave given this kind of governance: they seemingly do whatever they want.