  Almost no modern software system is written from scratch, and developers are
required to effectively learn to use third-party libraries or software
services. Thus, many practitioners and researchers have looked for ways to
create effective documentation that supports developers' learning. However, few
efforts have focused on how people actually use the documentation. In this
paper, we report on an exploratory, multi-phase, mixed methods empirical study
of documentation page-view logs from four cloud-based industrial services. By
analyzing page-view logs for over 100,000 users, we find diverse patterns of
documentation page visits. Moreover, we show statistically that which
documentation pages people visit often correlates with user characteristics
such as past experience with the specific product, on the one hand, and with
future adoption of the API on the other hand. We discuss the implications of
these results on documentation design and propose documentation page-view log
analysis as a feasible technique for design audits of documentation, from ones
written for software developers to ones designed to support end users (e.g.,
Adobe Photoshop).
