I wouldn't by into such an ownership structure, though to be fair, google has such a structure and those that bought that at IPO have done very well so far.
From the risks section:
As a result of voting agreements with certain stockholders, together with the shares he holds, Mark Zuckerberg, our founder, Chairman, and CEO, will be able to exercise voting rights with respect to an aggregate of XX shares of common stock, representing a majority of the voting power of our outstanding capital stock following our initial public offering. As a result, Mr. Zuckerberg has the ability to control the outcome of matters submitted to our stockholders for approval, including the election of directors and any merger, consolidation, or sale of all or substantially all of our assets. In addition, Mr. Zuckerberg has the ability to control the management and affairs of our company as a result of his position as our CEO and his ability to control the election of our directors. Additionally, in the event that Mr. Zuckerberg controls our company at the time of his death, control may be transferred to a person or entity that he designates as his successor. As a board member and officer, Mr. Zuckerberg owes a fiduciary duty to our stockholders and must act in good faith in a manner he reasonably believes to be in the best interests of our stockholders. As a stockholder, even a controlling stockholder, Mr. Zuckerberg is entitled to vote his shares, and shares over which he has voting control as a result of voting agreements, in his own interests, which may not always be in the interests of our stockholders generally.