Due to the constantly evolving nature of Web-based Education (WBE) it is often difficult for educators to understand the issues, challenges, impact, and effort required to introduce WBE innovations. This lack of knowledge can contribute to the limited adoption and less than successful implementation of WBE innovations.
A useful read both for the model as well as for an indication of how (not) far we have come in 8 or 9 years of web-based education innovation. The article was presented in 2003, so presumably based on work done earlier
rWorld2 