Many Coursera online courses have an exam component. This raises the question:
Question How is a Coursera exam typically conducted?
It seems non-obvious to me how one would conduct an exam involving students who might be on different continents.
Having not used Coursera, I do not know what tools they use. However, I have been a part to online exams from both the student and instructor perspective using the Blackboard learning management system. I suspect that features like many (if not all) of the ones Blackboard supports are present in Coursera.
Features like these give instructors flexibility in offering the exam to students around the world, while still making it harder to cheat.
They will "cheat", however. No online course management system can prevent the student from using their text, notes, or another computer or electronic device to look up answers. The best defense against infractions of this nature are well-written tests (the kind you might write for an open-book or take-home exam).