Mnemosyne on the other hand is deceptively simple. It is basically your good old flash cards, only run by the computer. Except for the SRS business. This is explained far better on the Supermemo website, but the idea is as easy as this program: You learn best if you review a fact in the exact moment you are forgetting it. Obviously, none less than God can know when you actually forget any given piece of information. Most notably YOU would not know, or you would not have forgotten it! Spaced Repetition Software makes an educated guess, to the nearest day. Then it corrects itself based on your feedback. In Mnemosyne, this feedback is a number from 0 to 5, where 0 is "never heard this before" and 5 is "dude, like I'd ever forget that". Based on this, it brings up the difficult stuff more often and the easy stuff more rarely.
This may seem too easy to be worthwhile, but there is another layer or two to this. The program quietly corrects for your stupidity. If you tend to claim that this is really easy but next time you have forgotten it, the program notices. Likewise, if you tend to mark things for review too soon, the program will eventually figure out. It should also be able to track distinct groups of information and make separate indices for them. (Supermemo definitely does this, and Mnemosyne has categories too. I am currently testing it out.)
While the first repetition normally happens the next day, the later ones can come up weeks or months or even years later, so this is not a "fire and forget" thing. (The point is NOT forgetting, after all!) The program works optimally if you spend a few minutes on it each day. You may skip a day now and then without scrambling it, but for optimal effect it should be used every day. (We elderly people are all about regularity anyway, so I should be fine with it.) I am currently testing it with some Japanese cards I found for free download - it seems to be particularly popular among students of Japanese. I guess if it manages to teach me to actually READ the stuff, it can do pretty much anything. In which case you will probably hear about it again in a few months.