Key detail — unlike in the previous arrangement, he (and his heirs) will lose voting majority when he is no longer CEO or Chairman. 
<a href="http:&#x2F;&#x2F;www.bloombergview.com&#x2F;articles&#x2F;2016-04-28&#x2F;mark-zuckerberg-gets-to-control-facebook-a-while-longer#footnote-1461859887269" rel="nofollow">http:&#x2F;&#x2F;www.bloombergview.com&#x2F;articles&#x2F;2016-04-28&#x2F;mark-zucker...</a> (attempted to link to footnote 8)