Studies of Internet use continue to show a gap between those with and without access to the Internet and its resources. However, recent work indicates that this is not a straightforward divide about access; instead there are many variants of access, use, and presence online. This paper examines these variants, bringing together primarily US and European studies on the digital divide to identify social facilitators and inhibitors to online use that can inform policy and practice. This paper reviews research on who is and is not online, where access is gained, and what promotes or inhibits use of the Internet. This leads to identification of a number of interrelated social and technical factors that underlie access differences, including technical and social infrastructures, social networks, and content.