This wartime propaganda campaign by the British Government discouraged talking about sensitive material where it could be overheard by spies. It was devised to prevent morale sapping rumours from spreading during the 2nd World War. Inversely viral in a way, but intended to start a movement and encourage a set of behaviours that could be further amplified by the public at-large.
Another way companies research what consumers want is through customer surveys. Most of these surveys simply ask the customers what rewards or incentives would be most likely to get them to participate in a referral program. Marketers brainstorm a list of possible rewards to include with surveys, and also ask customers to offer their own alternatives.

Viral marketing is a customer-focused approach, so the first step is to identify the target demographic for a product and what they value the most in products, requiring marketers to research and analyze demographic data. During the Blair Witch campaign, the filmmakers and main marketing agents for the movie were accomplished film students. They examined what made horror movies compelling for the demographic of teens to young adults they were targeting, as well as explored how that demographic shared information. They used this information to focus on their product's mystery, and they concentrated their early efforts on the Internet where they knew they would have the best chance of reaching a younger audience. (See also Youth Marketing)

Alright, you’re ready to publish your video. You shot the footage, edited it together, added music and a voice over, and exported it for the web. The next step is to get your video online so your audience can start viewing and sharing it. You have several options for hosting videos online, and in this section, we’ll talk about some of the best ones.
Many voucher code web sites use a click-to-reveal format, which requires the web site user to click to reveal the voucher code. The action of clicking places the cookie on the website visitor's computer. In the United Kingdom, the IAB Affiliate Council under chair Matt Bailey announced regulations[46] that stated that "Affiliates must not use a mechanism whereby users are encouraged to click to interact with content where it is unclear or confusing what the outcome will be."
What does aperture mean for your video? When a lot of light comes into the camera (with a low f-stop number), you get a brighter image and a shallow depth of field. This is great for when you want your subject to stand out against a background. When less light comes into the camera (with a high f-stop number), you get what’s called deep depth of field and are able to maintain focus across a larger portion of your frame.
Among the first to write about viral marketing on the Internet was the media critic Doug Rushkoff.[16] The assumption is that if such an advertisement reaches a "susceptible" user, that user becomes "infected" (i.e., accepts the idea) and shares the idea with others "infecting them", in the viral analogy's terms. As long as each infected user shares the idea with more than one susceptible user on average (i.e., the basic reproductive rate is greater than one—the standard in epidemiology for qualifying something as an epidemic), the number of infected users grows according to an exponential curve. Of course, the marketing campaign may be successful even if the message spreads more slowly, if this user-to-user sharing is sustained by other forms of marketing communications, such as public relations or advertising.[citation needed]

Maintaining the warmth of human interaction at industrial and post-industrial scales is incredibly challenging. It comes naturally only for very-small operations.  Balthazar likely kept track of his customer referrals informally in his heads, or through simple bookkeeping if business was good. He would have had to recognize customers’ faces. If he were running a large organization or a popular ecommerce store today, though, he’d have to worry about fraud. How do you tell if someone is real? How do you keep track of everything?
^ Shashank SHEKHAR (2009-06-29). "Online Marketing System: Affiliate marketing". Feed Archived from the original on 2011-05-15. Retrieved 2011-04-20. During November 1994, CDNOW released its BuyWeb program. With this program CDNOW was the first non-adult website to launch the concept of an affiliate or associate program with its idea of click-through purchasing.
^ Semenov, Alexander; Alexander Nikolaev; Alexander Veremyev; Vladimir Boginski; Eduardo Pasiliao (2016). Analysis of Viral Advertisement Re-Posting Activity in Social Media. Computational Social Networks. CSoNet 2016. Lecture Notes in Computer Science, Vol 9795. Lecture Notes in Computer Science. 9795. pp. 123–134. doi:10.1007/978-3-319-42345-6_11. ISBN 978-3-319-42344-9.