Poloniex is an exchange, it allows you to buy and sell only cryptocurrencies, including Bitcoin. The platform provides operators with unique functions so that they can properly analyze the cryptocurrency market and execute their operations, it also offers additional services such as margin trading and even Poloniex loans, with respect to the latter, poloniex loans are those in the that investors borrow money to be able to buy cryptocurrencies in larger quantities. By doing this through Poloniex, investors borrow funds from other users, who of course earn interest on top of what they lend