Well, I do get it. We all want to make a buck, including employees and owners.
It is just a matter of how much they want to sell and for how much and when.
Most of them got free or cheap shares pre-IPO so any amount is good money to them but if there are material deals in the works they are aware of, they either cannot trade due to insider trading rules, or they will hold as they are also greedy. At $12, I would sell too if I had the chance on this stock with Pincus back in April. Only makes sense at that price to offload my risk. As a CEO of a company, there are still many forces outside of your control so human nature says protect some of my personal wealth and diversify. Smart move.
At sub $7, I may think twice. I have worked in companies where I received free pre-IPO shares, IPO'd at $15, dropped to $3 in a year, then up to $25 year 2 after major deals done. Deals take time to execute. I did not sell at $15. I did not sell at $3. I waited and afforded a down payment on a house.
Excluding the Exec's. The young staffers and programmers who receive say 10,000 options or RSUs (they apparently don't get a lot), can sell at $7 to get $70k gain (before tax) now, or if they work hard there and make another hit, the stock can go to $14 in a year and they may double their money and put a down payment on their own house or a fancy new car or vacation. When you are in a company, you know more so investing in the company is less of a risk as you do have a better pulse on what is going on. If you leave, then owning shares in it becomes risky as you know less of the company's "real" opportunities.
All I am saying is if you see a lot of selling at sub $7, then that says a few things of these Zynga employees' belief in the company. If you can predict that, then you must be an insider. If not, then just a guess. I doubt 100% of them will sell 100% of their holdings and sell hard next week. The lock up just allows them to legally sell. It will become more volatile for sure.