21 Marketplace (formerly Earn) is a website where you can sign in and be paid for doing simple tasks and replying to simple paid messages that you receive every day. They are paying you for every message that you answer. You receive 1 dollar for one message answered. On the average you receive 1 message to answer every 2-6 days, some years ago there were many messages to answer. I can say that I have made with this website 0.06 Bitcoin in a year some years ago for answering simple messages that they have sent me every 3-6 days. They questions that they are asking you in their messages are very interesting. This website was from the very beginning a good idea, receive money to read and answer to (some) emails. When they started the name of the 21 Marketplace was Earn.