What is a cryptocurrency exchange? Well your about to find out. When you think of an exchange think about it's counterpart the stock market. As a matter of fact it works in the same way with the same fundamentals, the only difference is what? It's trading cryptocurrency. There is another aspect they are and not all decentralized which means it would take a quantum computer to hack them. Whether it's decentralized or not just remember some exchanges can be open to hacks like "Mount Gox" but that is the centralized system's. But on the upside there is now a lot of security implementations to try and stop compromise. So if your looking to trade your coins just look into decentralized cryptocurrency exchanges. Also here is a video overview of the topic feel free to reply.