Herbalife is an example of networking used as marketing. Their sales model consists of basically this: A distributor purchases a certain amount of Herbalife packages from a higher-level distributor, and is responsible for selling them. The money earned belongs to the seller. One of the best ways of selling is to sell a bulk order to someone, who will then go through the same process.
If you think the above sounds like a pyramid scheme, you've gotten the point. If you've ever seen an "Earn money fast from home!" advertisement, it's very likely that it is an example of this kind of thing.
As described above, Herbalife is a weight loss treatment of questionable effectiveness.
In Russia during the Perestroika and post-Soviet times, Herbalife was ubiquitous. Very few had any sort of money or any way to earn it, so this sounded like a very attractive proposition. Before long, distributors were everywhere and customers were nowhere (or few and far between), and the saturated Herbalife market collapsed. This shows very effectively that Herbalife is indeed a good example of a pyramid scheme.
Now, whenever one visits Russia and sees an "Earn money fast!" type of ad, it will often also say "Not Herbalife!"(There's no TM. The word has entered the vernacular).