In the phase of evaluation, the instructor is to face each student. Thus, if an e-education is realistic/practical, it is either
omits evaluation, or
obliges the instructor to face each student in the phase of evaluation.
"Facing each student" is a problem of educator's capacity.
And the educator's capacity particularly determines the size of e-class.
In this sense, evaluation becomes a constraint on capacity of e-education.
If an e-education includes evaluation, it is going to determine the quota of students.
Thus, it is the evaluation that discriminates "web-based education" from "providing educational web pages".