Major changes on the Web in recent years have contributed to an abundance of information for people to harness in their learning. Emerging technologies have instigated the need for critical literacies to support learners on open online networks in the mastering of critical information gathering during their learning journeys. This paper will argue that people will have to adapt to using information in a new way and will advocate the movement by learners into and inside information streams on open online networks. Their own control and aggregation of information, preferably through human mediation, should provide information not only relevant to their learning, but also slightly unexpected. We will highlight why this serendipity is important in a learning context and also take three emerging technologies under the loupe; recommenders, RSS and micro-bloggers, and their effectiveness in supporting serendipitous learning on open online networks. (Contains 2 figures.)