Professor Halderman's course on voting security and history was quite interesting and when I took it during the 2012 election season is was especially significant since talk of voter fraud was common. The course consists of 40 video lectures and 5 quizzes. The course material itself wasn't difficult and while there was a companion book that was recommended you could do well with just the materials from the video. The level of the course was basic and did not really go into the technical details of the voting systems and subsequent attempts at breaking them. This isn't a criticism because to be honest I would have found the course boring if it had been presented that way.
The course starts out going over methods of voting used in the past. The basic idea of each week is the same. You are asked to view each video with the security mindset, i.e. asking yourself what could go wrong with each voting method. After an overview of each method itself Prof Halderman goes over ways that the system could be broken and manipulated. What I really appreciated is the experience that the professor was able to bring to the later lectures since he was part of a team that was able to break some DRE voting machines that were considered impenetrable.
My biggest complaint with the course is related specifically to the video lectures. Professor Halderman frequently interrupts himself with a number of "umms" which can be quite distracting. The content of what he is saying is fine but I think that for subsequent offerings he would do well to redo the videos to improve the flow and pacing. Once you become aware of just how many "umms" there are in a video (sorry!) it becomes even more distracting. Some students were upset by this much more than I think was necessary, at least from what I gathered by their posts in the forums.
This is another course, similar to the IHTS course, that I think is a good place to begin your mooc journey. I don't think it is quite as good because the IHTS videos are better quality. The course staff also hosted a few Google+ hangouts which allowed some students to interact directly with the professor. I appreciate it whenever I see the professor go out of their way to make an effort to connect with the students. In a medium like this that isn't always possible but trying to develop some sense of interaction goes a long way to making these feel more like college courses.
Overall this is a solid, fun course to take if you have a moderate interest in the history of voting or voting security.