Does anyone remember the old Faberge shampoo commercials? "And you'll tell two friends...and so on..."
SMM is built upon the idea that if someone knows about your business, they will tell a friend. Except that they are telling hundreds, sometimes THOUSANDS of friends about your business in a matter of seconds. Their friends are now looking for your business, and all without you having to intercede or be involved. This is a general description of inbound marketing. People finding your business based on referrals, reputation, and presence.
This is the very heart of smm. Social networks of people forming "marketing teams" to advertise your business for you based on their experiences. Compare this to outbound marketing whereas a business looks for prospects and clients/consumers actively through traditional sales methods such as cold calling, print ads, radio/tv and trade shows.
Shampoo teaches about smm:
"And you'll tell two friends...and so on, and so on..."