Encyclopaedia and Hypertext - Hypertext as an object of philosophical reflection. The three main research topics are From Encyclopaedia to Hypertext, Hypertext and Text Theory, and The Image Atlas of Aby Warburg.
Hipertulia - Forum whose aim is to introduce hypertext and hyperfiction to the Spanish-speaking public. Includes some articles in English.
ht_lit Mailing List - Instructions on how to join ht_lit, a low-traffic but valuable list a lot of hypertext theorists are members of.
HyperContent, HyperJunk - "Hypertext theory as if the WWWeb matters". Includes a timeline of hypertext evolution and a concise taxonomy of varieties of hypertext, with examples and links.
Hyperizons - Theory and Criticism of Hypertext Fiction, by Michael Shumate.
The New Review of Hypermedia and Multimedia - Annual peer-reviewed review journal on the practical and theoretical developments in hypermedia and hypertext. Of interest both to technical developers and to esthetical or cultural theorists. Print journal, abstracts available online.
Resource Center for Cyberculture Studies - An online, not-for-profit organization whose purpose is to research, study, teach, support, and create diverse and dynamic elements of cyberculture. Book reviews, and bibliographies.
Suite101: Lit[art]ure - Interviews with new media poets and net artists, reviews of websites, criticism, articles and discussion. Part of Suite101, a volunteer editing project.