Closed corpus AH systems demonstrate what is possible to achieve with adaptive hypermedia technologies; however they are impractical for dealing with the large volume of open corpus resources. Our Knowledge Sea project explores social navigation support, an approach for providing open corpus personalized guidance that is based on past learners’ interaction with the system. This paper presents the most recent stage of our project that focuses on using annotations for social navigation support. We present most recent version of Knowledge Sea that implements annotation-based social navigation support and reports the results of several classroom studies evaluating this technology.