A composer interface allows a user to provide input, such as text data, to the social networking system. Based on context information associated with the user and received input, the social networking system presents candidate data items to the user. Selecting a candidate data item allows the user to include the candidate data item in the input. Examples of context information include: users connected to the user, profile information associated with the user, and geographic information associated with the user. The candidate data items may be presented based on the probability of the user selecting a candidate data item.