Although I really do believe EOS could handle that with ease. Now, the day after... I do not think Mark Zuckerberg ment that he wanted to go Free and Open Sourced with Facebook on the blockchain.
But it seems at FB they are considering a Cryptocurrency and decentralizing it all on a blockchain. Sounds a bit like what we already have. Good that Steem is the market leader in this technology.
Yet if mister Zuckerberg wanted to get some of that market and needed a system that could handle it, EOS would be it. Although I do expect Steem to develope into a multi-threading half a second blockchain.
Then FB users would move to Steem. Looks like centralized companies are becoming a thing from the past. (And I am sober now while typing this, although there is still noise inside my head caused by the common cold.)