My friend is doing part-time promotion, sending 3 messages a day, getting 30 yuan a day, just sending friends. So the question is, how does this company make a profit?

Your friend must have paid a deposit when he did it. As for profits, I tell you clearly that this is a scam. First of all, the top management will develop many offline companies to attract more people. Suppose a person is 200 yuan, then his salary will be available, and then his circle of friends will have pictures of his salary drying, thus attracting more people to join. After you have done it for a while, his senior management will tell you what the good news is and which companies are on the right track.