A form of marketing where the user of the product or service helps to spread the word. The birth of the Web meant that ideas could spread quickly from one person to the next. Clever marketers turned that ability of the Web into one of the most powerful marketing techniques ever.
A great example is that of Hotmail. The early success of Hotmail is largely down to a small “Get your private, free email at http://www.hotmail.com” message at the bottom of each email sent from Hotmail. The more users they added, the more “Get your…” messages were being sent out into the world.