The on-line exams are great! However, to minimize cheating (students searching answers posted on-line), consider allowing teachers the ability to tweak the exams, making each exam unique to their academy (yet still similar to others)...this would reduce students ability to cheat.

Also, allowing teachers to share these "edited exam questions" with each other would allow a question to have multiple forms and possible solutions. This would minimize a student's ability to cheat.