well i think they are, there is a rumor that Zuckerberg is investing in bitcoin. And hell yeah they know that it exist.
They are the most capable of buying and holding a lot of bitcoins so it would make sense if they are investing to bitcoin specially if its mark Zuckerberg since his investments and assets are mostly through internet I couldn't see any thing wrong for him to invest also in bitcoin aside from his very humble and simple lifestyle like he doesn't want to feel richer anymore.