Surely can make money la, why cannot? It is up to you whether you want to make such money or not or do you like such life style or not.

MLM got many types:
1) product based, sell product to earn profit. People joined is either want to become a distributor like you or just want to be a user and get the products for a lower fare.
2) member based, look for more member to join below you to earn profit. People joined has a sole objective that is to make pure profit in shortest time possible.

Most of the trick they will use to lure you in
A) will highlight your health issue, telling you how health concious you should be, make you start worrying about everything else you eat is crap except their vitamins, bluff you are all the true story about some aunty getting cancer and cured, and you will buy vitamins from them.
B) they will lure your basic instinct of greed, make you worry, and from your weakest point they start invade you with the "solutions" they have. Example they will show you their weekly pay cheque, the sport cars their "good friends" driving, lecture you about horror stories in an employee life and finally hard code the definition of success as a member under them into your brain.... etc.

Doesnt matter about their system good or not(you wont know good or bad as they sure bluff sky cow about their company), they surely design a system and beautiful numbers to convince people. As i said before, I can also design a system to sell chicken rice and make big money.

For myself, i rather become a farmer or chicken rice seller.

This is very hard to know one company legality as they usually have some way to cover their dirty sh!t. Amway, Cosway, DXN, all listed MLM company, sure. But some famous MLMer will show pictures of our leaders and their CEO chatting, opening ceremony, whatever international cert, things like that, to gain our trust to them, even thou it is illegal.

So most important things to remember:
- DO NOT believe in anything they show you. Including photostate copies, website, anything.
- DO NOT believe 100% to what they told you, we should always look for the truth ourselves, or at least learn how to use your brain to process the information received.
- DO NOT sign anything, pay anything if you have doubts, but if you feel really convinced, do give yourself more time to think, or ask other people opinion.
- DO NOT just listen to one particular group of opinions, you have to seek different people opinions, you see, some people encourage you, some(like the LYNer here:) ) will discourage you and shoot you kaw kaw. And from these people you will be about to know what most people is thinking.
- DO ask yourself what you really want in life, dont let other people fix it to you, especially your MLM friends.
- DO remember that the internet is a powerful tool of information.

My 2 cents