https://signalvnoise.com/posts/2585-facebook-is-not-worth-33...
It's worth almost 17 times more than that now. Market cap is not a perfect metric because it doesn't capture the depth of the market willing to buy but coins don't make that any different.
It's an absurd metric made worse by the fact that more coins are issued every 5 mins. If price remains the same virtually all coins will go up in marketcap regardless.
What company issues new shares every single day?
The valuation of a company is determined based on its financial performance and, ultimately, by its ability to generate cash for shareholders. (Keep in mind that, unlike cryptocurrencies, companies generate profit for their owners just from their daily operations).
That overall valuation drives share price. Equity investors consider how valuable they think a company will be in the future and back into a price they're willing to pay per share from there.
Market cap is a meaningless metric for crypto since nobody would ever want to buy all the Bitcoin in the world and hold it for ten years. What would be the point? It won't generate cash flow during those ten years, and it almost certainly won't be worth more in ten years - with one person hoarding all the Bitcoin in the world nobody could use it for any transactions and people would lose interest.
Case in point, nobody talks about the market cap for USD or other currencies. It just doesn't make sense for assets that are only valuable as a medium of exchange.