He's worth about 26 billion, I'm pretty sure that even if he cashes out 5 billion that is still plenty of incentive to deliver. He's waited 8 years, I don't consider that a "rush" to cash out.
One might argue the eight years of waiting was simply to get to this point, when income had reached its peak ($1BB), and where FB could IPO and certain parties could extract maximum profit. The "rush" is cashing out just as the company opens its books to the public.
If FB revenues continue to go up, then I'm wrong. But unless Facebook "finds" a novel business model I do not see revenue continuing to climb; I believe we are at the peak, and now begins the descent. If he waited eight years, then why not wait a little longer? I believe there is a reason now was the time. Time will tell.
