Almost half of the students, based as far afield as Cornwall and North Yorkshire, got an A or A* in the Southern Examining Group exam.
The nine-month course is taught via a website that has different web-boards for each "class" of 15.
A tutor runs each web-board, posting assignments and deadlines. Students then post their work on their class's web-board and get feedback on email.
There is also a chatroom on the site, so students can talk about the material being studied or simply socialise with each other.
The final exams are taken at a local school or college.
Eight of the students on the course were under 17 - one had been excluded from school.
But most were adults who found it difficult to attend evening classes due to family or work.
Dot Rodman, 47, a childcare development worker from Sheffield, was diagnosed dyslexic when she joined the course.
She said: "I had learned to get around my problems but decided it was time to face them head on. This course is brilliant with fantastic support. There were strategies to help me tackle dyslexia as part of my learning programme. I was totally shocked when I heard that I had been awarded an A*."