Cramberry is a free flashcard creation service. Just as with similar services you have to input the items you wish to appear on your flashcards. Cramberry flashcard sets can be shared with other users. One feature that make Cramberry different from other flashcard services is Cramberry tracks which cards you answer correctly or incorrectly. This feature allows students to eliminate cards they know and focus on the ones they don’t know.

Here are some other free flashcard services to consider along with Cramberry.
Muchobeets
Study Stack
Knowtes