Actually currency is the same thing. The dollar has value because we all agree it has value. It's not based on gold any longer (though one could argue it's based on oil). It's based on a host of indices that we, as a group set. And those indices are traded and have a set value. Decided by the buyer (us) and seller (us).
I'm not complaining. I'm just pointing out that all of our economy is based on the same principe/model; as long as the vast majority of the group (us) believe the dollar is worth something, it will be.
Anyone who invested in FB at any time (and that includes the big boys) believed that FB was a good investment. In other words, they believed the hype and didn't understand the business. Until someone who they trusted came along and told them to bail. And here we are.
I actively trade. All the time. But FB I didn't touch. I asked myself, at ANY time have I ever clicked an ad on FB? The answer: "No". That meant FB is vapor. People are betting that people (all of us - including the people making the bets) might, sometime in the future click on ads. Or that FB might come up with something. Something. (And I bet it's gonna be selling out personal data - what we browse, like, etc, etc. It's the only real value FB has).