Research has found that loneliness is associated with both increased Internet use and Internet abuse. Causality is hard to determine. This article presents evidence from research on computer-mediated communication, social anxiety, and Internet-specific survey and field studies that support two opposing hypotheses. Loneliness is a byproduct of excessive Internet use because users invest in online relationships at the expense of real-life relationships. Lonely individuals are drawn to some forms of interactive activities online because of the possibilities of connectedness, companionship, and communities they offer. Limitations of these hypotheses and the potential benefits and risks of Internet use by the lonely also is discussed.