Consumers increasingly want to patronize the types of companies that demonstrate an alignment with their personal values. This marketplace shift can be largely attributed to consumers of Millennial age, who are now the nation’s largest living generation and make up a quarter of the entire U.S. population. Shaping the economy with an influential $200 billion in annual buying power, Millennials demand a degree of “like-mindedness” from their preferred manufacturers and major brands, namely around things like corporate social and environmental responsibility. But how is the consumer informed of those values? When it comes to communicating an alignment with personal values, it doesn’t get more personal than social media. Today, two-thirds of Millennials, the most technologically inclined generation in history, currently use social media to engage around CSR issues. For major purpose-driven brands and organizations, social media is an invaluable tool for reaching conscious consumers (including the more than nine-in-10 Millennials reporting a willingness to switch brands to one associated with a cause) with targeted, effective social campaigns. REI, for example, inspired over 6 million consumers to #OptOutside this past Black Friday (up from 1.4 million last year) with its second annual hashtag-driven campaign calling upon consumers to go outside instead of shopping. The company kicked off 2015’s inaugural campaign by closing all of its locations (and going offline) on Black Friday and giving consumers access to REI’s Explore the Outdoors platform — a search tool with BatchGeo-like functionality allowing consumers to find outdoor activities near them. Simple and powerful, this campaign “walks the walk” to reach conscious consumers who will not only buy products from REI, but who align with their social values, growing beyond the brand into sort of a social media movement all its own. At my company, TerraCycle, we too have continually seen the value social media can bring to our partners’, and our own, sustainability and eco-activism efforts. This past spring, TerraCycle and Open Farm celebrated Earth Month with the #RecycleWithOpenFarm social media contest. The contest engaged customers on the recyclability of Open Farm packaging by calling upon pet owners to snap a pic of their pups recycling and entering the photo using the #RecycleWithOpenFarm hashtag on Instagram for a chance to win a three-month supply of Open Farm pet food. The series of entries were so overwhelming, we rolled out a second phase to the contest, #RescueWithOpenFarm. This time, the prize was a donation of pet food to the animal shelter of the winner’s choice, also highlighting the brand’s commitment to animal welfare. This kind of engagement is invaluable for companies seeking to raise awareness to their eco-conscious and cause-driven missions in a competitive marketplace where social responsibility has become the baseline, rather than an aspect that automatically adds value. It is a testament to the power and effectiveness of eco-activism on social media, and that consumers are receptive when their favorite socially responsible brands engage with them in educative, informative ways. Creating transparency and relating purpose to consumers, social media is a powerful tool in its ability to tell a brand’s story in real-time, allowing consumers to have open conversations about the social responsibility records of those brands, and other salient subjects in sustainability.