Flashcard DB is one of the most well-designed free flashcard programs that I’ve seen on the web. Flashcard DB, like most flashcard programs, allows you to browse existing sets of flashcards or create your own custom set of flashcards. What makes Flashcard DB different from its competitors is the study methods that can be used with the flashcards. Flashcard DB allows students to study using the Leitner System or the Graded Space Repetition Method.

The Leitner System works by flashing the flashcards that a student doesn’t remember more frequently than the flashcards that a student does remember. The image below diagrams the system.

The Graded Space Repetition Method works in a similar manner to the Leitner System. The difference between the Graded Space Method and the Leitner Sytem is that instead of a simple right or wrong system, in the Graded Space Method the student grades how well they think they know each flashcard. This gives a human input element to the frequency with which each flashcard appears.

Flashcard DB is a free service and registration require only a username, password, and an optional email address. There are currently more than 16,500 sets of flashcards on Flashcard DB.

Applications for Education
Flashcard DB provides students with two excellent study methods. Students can create their own flashcards or you could create a set a flashcard for students to study.

Here are some other flashcard services that may be of interest to you:
Muchobeets
Study Stack
Cramberry
Quizlet