How to run a platform to match 4 million writers of stories to 75 million readers? Use data science. Make money by doing deals with television and film makers and book publishers. The case describes the challenges of matching readers to stories, and of helping writers to produce better stories by supplying feedback on their chapters as they write, all by processing a billion data points daily. But it's hard to acquire new customer groups when algorithms have a bias to replicate the tastes on which they are trained.

Legendary, the Hollywood studio responsible for such hits as Jurassic World and The Dark Knight, decides to take the marketing of its films in-house, and to market them fan-by-fan. Owner Thomas Tull acquires the big-data-in-sports firm started by Matt Marolda and appoints him to run marketing analytics for Legendary. The methods perform well in the motion picture market. Other Hollywood studios want to lease its services, and firms outside of entertainment express interest. Marolda and Tull consider setting up Legendary Analytics as an independent consulting business. At that point Dalian Wanda, China's largest entertainment and real estate conglomerate, buys Legendary. Should Marolda focus on China or the diversified U.S. market?

Instacart is testing an Uber-style solution to the challenge of building a home-delivered grocery business. It is backed by $220 million of venture funding. Will this model succeed where businesses like Webvan failed? What are the questions that this exploratory venture needs to answer?

This case examines the changes employed by YouTube to make the massively popular site more attractive to brands. Building from its base of amateur, user-generated content, YouTube had turned to experimenting with professionally-made content and organizing its videos into channels. But it still struggled when it came to capturing advertising dollars to its online video platform. The social video website wants to be a 'brand safe' platform which major marketers use to advertise their video ads. Should major brands switch a significant portion of their TV advertising budget to online ads on YouTube?

In 2013, TripAdvisor was the most visited online travel site in the world. It hosted a massive repository of information on hotels and travel services, and provided millions of reviews written by consumers. Consumers were becoming increasingly motivated to read and write reviews on TripAdvisor, largely as a means of informing other consumers about their personal experiences, but also to praise or complain to hotels about their experiences. In response, hotels were investing more time and marketing budget on managing the quantity, quality and location of online reviews, with particular attention paid to TripAdvisor.

Local businesses' experiences with using Groupon to promote themselves ran the gamut of roaring success to absolute failure. Why is there such a large range in outcomes for firms that used daily deal sites such as Groupon? This case examines the effectiveness of online daily deal sites from the point of view of local businesses.

What is the value of Bluefin Labs's social listening data to Twitter? Acquired by Twitter in 2013, Bluefin had built a system that gathered millions of online comments in an effort to develop new metrics for TV programs and brand advertising. With data from Twitter and other social sites, expressions, not just impressions, could now be aggregated, measured, and used to calibrate brand performance and to sell media time. A second objective of the case is to understand the implications of social TV viewing, the audience engagement that results when people watch television with a smartphone or tablet in hand, participating in a virtual community of real-time TV watchers.

Four businesses had, by 2012, grown to dominate the infrastructure that all firms rely on to reach online customers. Will the balance of power among the four persist, will one take command at the expense of the other three, or are all four more vulnerable than they seem to outside forces? What are the implications for the pace at which consumers go online? Amara's Law claims that we tend to overestimate change in the short run, and underestimate it in the long run.

Google search had helped Demand Media grow to be a $1.9 billion online publisher. Then, social media and smartphone apps began to change the way people navigated the Internet. How should Demand Media respond? The business ran on a radically new model in which a stable of 10,000 freelance contributors supplied content, the Internet's search engines brought it 75 million readers each month, and advertising generated revenue. It took the guesswork out of content production, with algorithms that indicated which topics were being searched and created content accordingly. Demand treated its 5,000 online articles published per day as an investment, not a cost, a reversal of the traditional media model. In addition to being able to infer consumers' interests with its algorithm, the company had a formula for estimating the lifetime value of each piece of content. As the business models of print and broadcast media declined, Demand had figured out how to leverage digital and social media tools to bring down the costs of creating content and to find an audience. In spring 2011, executives at the five-year-old company were pleased with the company's billion dollar IPO, the biggest Internet IPO since Google's, but changes in consumer behavior on the Internet were obliging a review of the model.

Cheezburger Network was a Web publisher of humorous, user-contributed content, using social media for dissemination, and selling advertising against the traffic of 1 billion page views per quarter. In January 2011, it raised $30 million in venture capital for the network of 50 websites that featured an entertaining array of user-generated content. Beginning with a site based on pictures of cats with whimsical captions, it had grown into a small but impressive digital empire, riding waves of viral content. CEO Ben Huh prided himself on his ability to go from idea to implementation in just a few days, but this just-in-time method made strategic planning difficult. Profitable from day one and with $5 million of revenue across 50 brand identities, Huh's challenge was to evaluate his growth to date, to look critically at the digital media landscape, and to figure out how to best to spend the $30 million.

Executives at Ford wondered if social media could be the marketing solution for the launch of the youth-oriented 2010 Fiesta. But with social media came a ceding of control. Some at the company believed that if Ford was going to move beyond its conservative brand image for the launch of the new subcompact chances had to be taken. Others erred on the side of caution. Chantel Lenard, Ford's Group Marketing Manager for Global Small Car and Midsize Vehicles and Connie Fontaine, Manager of Brand Content and Alliances championed a new approach for the new vehicle and set into motion a comprehensive 6-month social media initiative targeting a younger, ethnically diverse, and urban-based market, called "The Fiesta Movement". In doing so, a large portion of the marketing campaign was handed over to 20 and 30-somethings across America, and Ford had to acclimate to a new way of doing marketing. To what extent should the company guide the activities and messages of their army of bloggers? The case is set two months into the Movement, as the team evaluates the metrics from YouTube, Twitter, Facebook, and their website, and wonder if they're doing everything they need to do in order to make the Fiesta a success with a new target market.

In late 2008, executives at Coca-Cola had to decide what to do with a fan-created page on Facebook that had amassed over one million followers in three months. From a legal point of view the fan-created page was in violation of Facebook's terms of service, because a non-copyright holder was using the imagery and logo associated with a known brand. Facebook contacted Michael Donnelly, Group Director, Worldwide Interactive Marketing for The Coca-Cola Company, to let him know that he was in the position to take down the hugely popular fan-created site or, conversely, he could take it over and make it an official marketing channel for the company. Coke was already revisiting its social media policies, with the Diet Coke and Mentos user-generated video incident fresh in its memory. Those videos, which featured elaborate geysers with Diet Coke as their main ingredient, were among the most viewed online videos at the time but were not initially sanctioned by the company. Donnelly knew that opening up the brand to creative consumers was necessary, but he and his team had to figure out how and to what extent they should do so while still protecting one of the world's most valuable brands.

Global brands such as L'Oreal and Oil of Olay dominate China's skin care market. A Chinese domestic brand, after some success in partnership with Sephora in Europe, aspires to challenge the French and U.S. brands' hold on the China market. It must decide how to segment the market, how to position against global assurances of quality and purity, and how to balance its Chinese heritage claims with claims of modernity. The China skin care market is growing extraordinarily fast. Is that an asset or a liability?

How does a small business set its online media budget? The HBS Executive Education Division can be viewed as a small-to-medium sized business unit with annual revenues of $107 million. As we watch it change its culture, practices, and organization from offline to online marketing, we have an opportunity not simply to see the metrics used in online marketing budget allocation, but also the stresses involved in the birth of a new go-to-market culture.

When social media propagate a complaint about poor customer service, an international media event ensues. How do viral videos spread and what can firms do about them? This case dissects an incident in which a disgruntled customer used YouTube and Twitter to spread a music video detailing United's mishandling of his $3,500 guitar and the company's subsequent refusal to compensate him. The song was called "United Breaks Guitars." Within one week it received 3 million views and mainstream news coverage followed, with CNN, The Wall Street Journal, BBC, the CBS Morning Show, and many other print and electronic outlets picking up on the story. The mechanics of viral propagation are uncovered and the limited opportunities for response by the firm are revealed. The case supports the notion of the Internet as an insurgent medium, better at attack than at defense.

Executives at Sony Music Entertainment faced a dilemma: a user-generated video featuring controversial artist Chris Brown's music was netting millions of views per week on YouTube. Sony held the copyright to the song, and was entitled to issue a takedown notice to the party that uploaded the video. How should Sony act? This case looks at the issues faced by marketers in an environment in which consumers disseminate content without the assistance, or approval, of gatekeepers.