Social media, or communication from many-to-many (thanks, Shirky, for that definition!), has allowed for more rapid dissemination of information and subsequent action. This can be both a good thing and a bad thing. The anti-vaccine movement, for instance, has rapidly spread the false information that vaccines can cause autism and anti-vaccine posts and memes are constantly shared on Facebook and other platforms. People can sort themselves into groups with like-minded people and share the information they have found among themselves.
Social media can also be used to raise awareness about health issues. For example, the Ice Bucket Challenge, spread rapidly during the summer of 2014 and rose over $156 million for ALS research. This campaign increased usual donations over 800%! By tagging posts with the hashtag #icebucketchallenge, people were able to view (sometimes) hilarious videos of people that may not have even known. And while most people only interact with their small network, the interconnectedness of the networks allowed for the challenge to spread across the globe.