In our generation we can consider facebook is late from the platform of relearing sa Facebook coin, but once it was started. I am pretty sure it will be a bang. Many people get touch in using facebook; from this many people can be engaged of using cryptocurrency in facebook which is a great thing in a increasing numbers in our community.
I know that facebook has alot of community and users. But we cant be sure that they will adopt crypto space once facebook started their own blockchain. But for the sake of crypto improvement, I know Fbcoin will be on hype and this is something that can contributed in the increase of the market cap. Lets be clear that Mark is a known person and lots of influence. Adoption could be easy when they release it but again, still 50\50 chance about it. Lets just wait and see if they will really release.