This paper presents a case for the importance of sustainability in HCI as it relates to the Web. So far, the discussion about sustainability in HCI has focused on environmental aspects. However, our belief is that cyber-sustainability is much greater than this. We argue that to address cybersustainability correctly, the principles of sustainability should be considered in relation to 3 concerns: 1) environmental impacts, 2) psychological impacts, and 3) the worldview that the Web tends to promote. Several broad implications for more sustainable Web development are proposed.