The integration of information resources into clinical information systems may be based on a variety of approaches, including what is practical to provide, what is hypothetically useful, and (based on user studies) what is empirically useful. Resource selection may also be based on the user's context (role, task, patient demographics, concept of interest, etc.). Two years of log files showing the context-specific use of information resources, especially via use of an infobutton manager (IM), were examined for patterns of usage. 3483 known unique users (and an unknown number of anonymous users) accessed information resources 65,128 times, including the use of the IM 21,907 times by at least 2367 unique users. Links provided in response to empirical information needs accounted for 16% of the total links and 32% of the accesses to information resources. Links that were provided based on patient demographics accounted for 29% of the total links and 13% of the accesses to information resources. Links that were provided based on the users concept of interest accounted for 21% of the total links and 13% of the accesses to information resources. Knowledge of observed information needs and of context attributes is useful for guiding automated selection of resource links by an Infobutton Manager.