The only question now is: what negative impact will this have on the startups? If you take a look at the recent squabble with Zynga and the introduction of credits, you'll see that Zuckerberg is bold enough demand 30% of revenue for a Paypal clone. Given Zuckerberg's history of changing policies like privacy for the worst, it wouldn't even be a surprise if he raised that to 50%. Would investing in YC startups be profitable if their valuations where cut by 50%? Would they even be worth that much knowing that Zuckerberg could clone it or demand even higher margins on a whim?
Instant personalization will likely see similar fees once YC is hooked on it. Though past performance is not an indication of future results, I have to say the future looks very bad for anyone embracing the Facebook ecosystem.