I just finished reading Grapevine, the book by the founder of Word or Mouth Marketing company, Bzzagent.

From Bzzagent.com:

Word-of-Mouth has been described as many things…so we thought it would be a
good idea to start with what it isn’t!

WOM is NOT: Street teaming. Where people hand out freebies or flyers
to you while you’re walking down the street.

WOM is NOT: Shill marketing. Where companies hire actors to create
staged conversations with consumers, without telling consumers they’re staged
(also known as "roach" marketing).

WOM is NOT: Spamming or fake online marketing. Where people send
e-mails to individuals who don’t want them, or companies post fake opinions
online in chat rooms, blogs, or review sites like Amazon.

WOM IS: Honest – Real – Powerful.

It’s something we all do everyday – it’s the way we communicate. It’s part of
our social fabric. WOM is the shared opinion about a product or service between
two or more people. Share your honest opinion, and you’re creating WOM.

Bzzagents get free stuff when they "Bzz" someone about a product.

Network Marketers get similar benefits, in many cases associates (aka Bzzagents) share the product that they enjoy with others, allowing the associate to earn enough money to cover the cost of her product.

Network Marketers have not (yet) come up with cool language like "Bzzing" someone about a product and then reporting the results back to "the hive", but it is virtually the same process. (At least the process I envision and teach to others.)

Kim Klaver recently wrote an interesting article on the subject as well. Read it.