Collaborative Course - This is a type of an online course that is taken online with others, participating in discussions, postings, etc. with a  definitive start and end date.

Independent Course - This is a type of an online course that is taken working with your instructor one on one.  Such courses have open enrollment.  However, once a student registers they have up to 12 weeks to complete the course from the date of registration.  This kind of course is designed to be completed in 8-10 weeks.