The 2014 ACM Recommender Systems Challenge invited re- searchers and practitioners to work towards a common goal, this goal being the prediction of users engagement in movie ratings expressed on Twitter. More than 200 participants sought to join the challenge and work on the new dataset released in its scope. The participants were asked to de- velop new algorithms to predict user engagement and evalu- ate them in a common setting, ensuring that the comparison was objective and unbiased, within the challenge.