1) Expect the angel and seed stage market to continue to stay hot. Newly wealthy Facebookers will likely contribute massively to early stage companies, which means building relationships with companies early and actually rolling up sleeves to add value will be a must for investors. If you're just money, you are toast.
2) Facebook will be hungry for growth in its ad business, and since it is running out of internet connected humans to connect to, it will need tools to make more out of each person. This will be a huge boon for companies like 33Across that monetize social data without being creepy.
3) It will get much harder for Facebook to recruit talent, since the promise of the pre-IPO stock pop is gone.
4) You'll likely see Facebook make a move to diversify revenue by breaking ground on a big new area. I'd say it has to be payments, because knowing who your friends are gives them a natural advantage in peer to peer. That data can also be used for fraud prevention because it's pretty hard to fake a person on Facebook compared to the normal behaviors and extended network of others.
5) Stories of how much money people made as early employees will trickle down to students, who will be less likely to join big companies and more apt to start their own businesses. Recruiting for banking and consulting will become that much harder.
6) The newfound wealth created by Facebookers will spur innovation around impact businesses in the sustainability, green, and social good areas--because if you don't need to work, you might as well work on something that makes the world a better place.
7) Expect more competition to Facebook. As crazy as it seems, the truth is that companies tend to take less risk, innovate less, and lose key employees after an exit. Entrepreneurs. May look to figure out what's next now more than ever before.
8) Increased regulator scrutiny of Facebook now that it has to make more disclosures about how it is doing and its methods of making money.
9) Investors will be looking at what Facebook does with it's cash. Facebook Ventures? Bigger acquisitions?
10) Goosed VC returns. Tens of billions of dollars of return should help VC returns a bit, but it will wind up widening the gap between the haves of the top quartile and the have nots of everyone else.