Ok so, everytime you take a look at a coin's price prediction with a google search, like for instance Cardano, you always have the hopeful heard that says "10$ by the end of 2018!" if not more, while some more rational people will say it's not possible, 2$ max, because with the supply of coins (which is 25 billion for ada according to cmc), a 10$ share would mean a 250 billion market cap.
I also use it as an indicator of a coin's ceiling. When Ethereum was making its run a few weeks ago, its market cap reached over half of Bitcoin's. I thought then that there's no way that Ethereum's value could double at that point, because that would essentially mean that it's as valuable as Bitcoin. It's a very rough metric though.
Actually marketcap has nothing to do with the value of the coin.For example,if we have a newly launched coin having a total supply of 21 million coins and now the coin's market price is just $1,then now its actual marketcap is 21 million dollars.If a person voluntarily places a sell order for $4 for that coin and buys that coin at that rate,then the marketcap of that coin is calculated by just multiplying the total number of coins with the last sold price of $4 and now the marketcap becomes $84 million dollars.
You can't really pump market cap value because increasing the supply is tantamount to decreasing the price. No entity can dictate a price either, because the market will want to pay what they think it's worth.
Either way, market cap is relatively meaningless, but could be used as a
somewhat accurate indicator of a crypto's overall value, and the general growth of the entire market.
