The current study investigated 29 first-year Japanese university students' usage of an online vocabulary notebook that automatically searched eight different word and phrase lists to provide students with reference information about their self-selected vocabulary. Over the course of a 14-week period, participants read English books and articles and added self-selected vocabulary that they wanted to learn to individual online vocabulary notebooks. The notebooks immediately and automatically showed whether the vocabulary appeared on any of eight different reference vocabulary lists. The distribution of participant vocabulary across lists was examined and participant surveys and interviews were conducted to understand usage of the system. Analysis of participant vocabulary, learner surveys, and interviews indicated that participants selected relatively high percentages of standardized-test related vocabulary (i.e. TOEIC and TOEFL), chose individual vocabulary items over multi-word expressions, and studied vocabulary items even when they did not appear on any reference lists. Learner surveys and interview results suggested that use of the system directly or indirectly influenced half of the participants' decisions about which vocabulary to include in their notebooks, though participants reported that it did not affect their choice of reading material.