How did I find out about this forum? Very little exists on the internet about Supermemo (At least compared to more popular and trivial topics), with the exception of the Supermemo site itself. This will not change in the immediate future, as the basis of Supermemo goes against conventional schooling techniques and methodology (Cram, test then purge; an intellectual bulimia, if you will). The point is: Supermemo isn't going to get more popular, so I've given up hoping that that will change.
Thus, I set up a "Google Alert" in my RSS reader to alert me when the word "Supermemo" is used on the internet. There are about 20 or 25 alerts per week, and most of them are warez sites or iPhone App reviews (There is a Superemo iPhone app, although I still prefer the Windows version). Other times it links to a forum. If possible, I'll try to contribute to the discussion and say more or less "you've found something cool, you aren't alone! Keep digging, you're about to hit some awesome treasure!"
By "rotations," do you mean using it only for a certain amount of time? For example, use it for 4 months at a time?
Supermemo is basically a hyper-rescheduling flashcard program. There are two sides to a flashcard: Question side and answer side. You see the question side (Which can also have pictures, video or sounds associated with it), and guess the answer. You grade yourself on a scale of 0-5 (How well did I recall that information?), and based on that grade, Supermemo schedules when you need to next review that information. Because the review intervals will quickly start spreading (Difficult information is reviewed being reviewed frequently, easier information being reviewed less frequently), you need to check Supermemo every day to see if there are any flashcards you need to review. If you skip a few days, you get a traffic jam of flashcards from the previous days you missed. Although there is a function to allow for missed days here and there, it is largely a program designed to be used every day. (This is one thing that turns many people off of the program)
I know for a fact that there are groups of medical students that use Supermemo to pass their various medical exams, and they pool together their flashcards to prevent a doubling of effort. I've never really investigated such groups, as medical knowledge is a very small niche that doesn't really benefit me unless I'm doing something in the medical field.
I have had trouble finding good sources for flashcards, but the more I use Supermemo, the more I am convinced that making flashcards yourself is the best choice. Why? Because before you can remember, you must first learn. By creating flashcards (And adhering to the various
principles of making flashcards), you are "chewing" and "digesting" the information, and a flashcard ends up being the nutrient left over, the fruit of your labor. I think of Supermemo as my "Save point" in learning. Study stuff, deconstruct and analyze it by making flashcards, save your progress by putting the flashcards into Supermemo.