Tradecoin is a trading platform where users use Bitcoin, ETH, etc. as an intermediary to trade based on the up or down of other coin on the trading floor. It means buying into coin types at low prices and selling them when prices rise. Then make a profit on the difference.
Investors can trade coins when they are listed on the floor. Coinmarketcap information is provided on this site. This is an overview of market capitalization of electronic money. You can find detailed information of each coin when visiting this web site.