Final answer:
Ryan's sharing of his favorite brand's promotional link leading to widespread message spreading exemplifies viral promotion, a common digital marketing strategy.
Step-by-step explanation:
After Ryan notices promotional offers on the website of his favorite brand and shares the link with his friends, the spread of the message can be described as a viral promotion. This type of marketing strategy involves the rapid sharing of an advertisement or brand message among people, mainly through social media and other digital platforms, with the intent that the content will become popular and widespread.
Viral promotion is part of today's attention economy, where advertisers use various techniques, such as associative learning, to attract potential customers and often rely on brand ambassadors to increase product visibility and credibility among peer networks.