We want to publish work that people share. All things being equal, people are most likely share practical and useful information. Useful, helpful content is most likely to go viral.
A study by the New York Times split the motivations for sharing into 5 main categories:
To bring valuable and entertaining content to one another. 94% of respondents carefully consider how the information they share will be of use to other people.
To get the word out about causes they care about. 84% of respondents share because its a good way to support causes or issues they care about.
To grow and nourish relationships. 78% of respondents said they share information online because it enables them to stay connected to people they may not otherwise stay in touch with.
For self-fulfilment. 69% said they share information because it allows them to feel more involved in the world.
To define ourselves to others. 68% share to give people a better sense of who they are and what they care about. (Note I think this is under-reported)