Noting that teachers and students who actually use an educational innovation in a classroom setting recreate it, this paper analyzes the implementation of ENFI (Electronic Networks for Interaction), an innovation that uses computers and local area networks in the teaching of writing. The paper presents ENFI's idealization in terms of its technological features and original visions for its use, and then its realizations. The paper identifies 16 distinct realizations of ENFI, and presents case studies of 2 of them in detail, relating each to characteristics of the setting in which it appeared. (Figures representing the conventional model of implementation, re-creation of an innovation in a social setting, two examples of ENFI computer screens, and six samples of student writing are included: 27 references are attached.) (RS)