There are few companies implementing MLM system starting from local networking. In MLM system the buyer also work as a distributor of the particular companies brand. Those companies are providing lucrative commission to those customers cum distributors and regularly trained them to make a chain of customers by networking.
The MLM companies who fail to succeed I think probably due to lack of planning, poor product presentation and overall something missing in the corporate leadership and among their co-ordinators. I think Amway is most successful company in MLM.
