Naturally, there are some disadvantages with the WWW. The disadvantages are:
The WWW is typically a wide open free for all type environment. There is no reason that Login privileges cannot be attached to the web server. This would limit the users to those individuals who are authorized (pronounced paid) for the right to use the course.
It is quite common to have the first course module open to the public for evaluation. If Joe Q. Public is interested, than further modules will carry a cost and enrollment.
Presently, if a HTML file can be downloaded it can be copied. This can be a big factor in making a decision on whether you want to put your lifeblood on the net. The solution can be to make many small files (which will happen naturally) which makes it next to impossible to copy all the files. For example, the small Ohm's law demo contains 24 files. It may become logistically impractical to download a complete curriculum.
Another tact is to have a large secure question databank. If the questions and answers are controlled, then the HTML files become reference material.
Restrict access after preliminary or introductory modules. If the person is still interested than they can enroll in the course. Login privileges can be utilized to allow only enrolled students to have access.
One thing that you will notice is how quickly the number of HTML files grow. A big problem is keeping track of the files, and the HTML "tree". There are programs available that will trace a HTML tree. The problem is tracking where the links go to.
Another area of concern is the naming of HTML files. A "standard" naming convention must be decided at the beginning of the development so that it is easy to track which file belongs to which. Another consideration is upper and lower case letters for filenames. UNIX is case sensitive whereas DOS is not. Someone who mixes upper and lower case letters in DOS will soon find that UNIX will hiccup on the filenames.
The WWW is only a delivery system at this time. There are no facilities for managing the courses. Course management is the part of the system that tracks the student's progress, grades and performs marking. This has to be provided externally by a database.
A problem can easily arise where the student wanders off the course map. There are no tools to restrict access to only the course content. The solution is to keep close tabs on the students progress through contacting the student on a regular basis.
There can be a substantial cost involved with translating your present databases and documentation to the HTML format. Your current question databanks may not easily translate. You may want to gradually migrate or do it all at once. Tough decisions....