I have spent lately some time reading finnish business discussion forums in order to get some hints how people are expecting economy and especially housing prices to develop. But today I spotted a thread about pyramid marketing and how those marketers have started to use violence in order to silence criticism. Here is an article about the incident (in Finnish)

It is so surprising how same old scheme works all over again. Promises of easy and passive income appeal to greedy and materialistic people - you just get money when other work for you. I have heard those marketing speeches as my friend contacted me long time ago and said that he has some new business and he would like me to join. Actually he did not say too much as there was a mentor who did speaking. It didn't take too long to realize what it was about. I felt somewhat mixed as I didn't now shall I throw them out or start to laugh to absurdness of the idea. Well, I did let them finish and I said that this "business" is not for me. They were persuading and finally they gave me a CD to listen. On that CD there was some fanatic guy telling how also you could get rich, all over again same story with different words.

This kind of business is in some cases illegal and in any case it is unethical and misleading. You don't have to have a degree in mathematics to see how impossible it is. It will benefit you only if you set up your own scheme. But do you want to make your living as selling over priced junk and sacrificing your friendships in name of recruiting? Sure it beats selling drugs but it is definitely against my ethics.

Some additional links for further reading:
Verkostomarkkinointi - Bisnestä vai huijausta?
What's Wrong With Multi-Level Marketing?
Plenty of critical material available, just use your favorite Internet search.