A limitation of current Web-based collaborative learning is the restricted ability of students to create and share individual annotations with annotated documents. Applying Web 2.0 collaborative annotation systems and analyzing students' annotation behavior has attracted attention to improve collaborative learning. This study designed a personalized annotation management system 2.0 (PAMS 2.0) for managing, sharing, and reusing individual and collaborative annotations as well as providing a shared mechanism for discussion about shared annotations among multiple users. The purposes of this study are three-fold: (1) to understand students' perceived attitudes toward the use of PAMS 2.0; (2) to investigate the effects of different annotation sharing scenarios on quantity of annotation and its influence on learning achievements; and (3) to examine the relationship between learning achievements and quantity of annotation. A quasi-experiment was conducted with two classes of college students for fifteen weeks. According to the results of the experiments, most of students in the experimental group are satisfied with the use of PAMS 2.0 for helping them create individual annotations and share their own annotations in collaborative learning context. Majorly students were interested in practical learning scenarios with PAMS 2.0 and thought this system is particularly useful for doing learning tasks. The analytical results of learning achievements show that the use of PAMS 2.0 can increase learning achievements in collaborative learning environments. Moreover, the results show that the influence of annotation on learning achievements becomes stronger with the use of the sharing mechanism. (C) 2010 Elsevier Ltd. All rights reserved.