Purpose: Libraries worldwide, including Hong Kong, increasingly use social media tools to introduce and promote their services and resources to users. Instagram, in particular, is used to target younger users. This study investigates the effectiveness of Instagram in promoting library services and university students' perceptions of the value of Instagram as a learning support tool. Design/methodology/approach: A major academic library in Hong Kong was chosen for this study. Library users' habits, perceptions, preferences, and views on Instagram's effectiveness as a learning support tool were compared in two age groups. The data were collected using a survey based on the 5E Instructional Model. Findings: Despite the significantly higher frequency of Instagram use by younger students, the results showed that Instagram was probably an ineffective promotion platform for either age group because of low user engagement, relatively neutral perception of Instagram as a learning support tool, and notably low user acceptance of Instagram as a promotional tool. Originality/value: Studies of student perspectives on various social media tools have increased; however, few have explored the use of Instagram, especially in Hong Kong or Asia. This study provides researchers and librarians with practical insights into current Instagram users' engagement, perceptions, and preferences and their view of its effectiveness as a learning support tool. The study also provides suggestions for improving the current situation. Copyright © 2023 Emerald Publishing Limited.

Purpose:Social networks provide convenient communication and connection among people, and they have become essential in college students' lives. However, problems also come along with increasing concern about trust and privacy issues. This research attempts to investigate the trust and privacy perceptions of university students when using social networks for learning purposes.Design/methodology/approach:This paper investigated the differences in trust and privacy perceptions between undergraduate (UG) and postgraduate (PG) students through an online survey with 96 subjects in Hong Kong. The authors used the Mann–Whitney U test to compare the differences between the responses provided by UG and PG subjects.Findings:The authors found that both PG and UG students were generally satisfied with the use of social networking sites (SNSs) for learning. However, PG subjects used SNSs more for learning and were more willing to exchange with classmates than UG and PG perceived higher value of SNSs than UG students. The authors also found a relative lack of privacy awareness of UG students.Practical implicationsBased on the study’s findings, the authors made some recommendations about the application of SNSs for learning purposes. The authors also suggest universities provide more guidance and training to students on the privacy issues of SNSs.Originality/value:Even though some previous studies have focused on studying privacy and trust issues on SNSs, studies that aim at university students in the context of Asia–Pacific are rather limited, especially university students' own trust and privacy perceptions on using SNSs for learning purposes. Copyright © 2021 Emerald Group Publishing Limited