The three most important facts about SuperMemo

SuperMemo is a learning method that makes it possible to learn fast and retain memories for years
SuperMemo is available as an easy computer program for Windows, Android, iOS, web browser, and more
SuperMemo is based on the science of long-term memory

This is how SuperMemo works

Collect learning material: SuperMemo helps you create collections of facts that you would like to remember.
Test your memory: SuperMemo tests your knowledge of individual facts and collects information about your memory.
Make smart repetitions: By understanding your memory, SuperMemo finds the optimum timing for review of the learned material. Each fact stored in your collection will have a unique pattern of review and repetition
Save time: With minimum number of repetitions scheduled for you by SuperMemo, you waste no time on repeating material you know well. You will be amazed with what speed and volume of learning you can reach. All that without a decrease in recall

In addition to the above core functionality, Windows version is your indispensable brain tool that helps you also:

read huge volumes of texts with minimum forgetting (see: incremental learning)
learn with pictures, audio and/or video
analyze your sleep
optimize your sleep for learning and optimize your learning using your sleep logs (see: Sleep Chart)
improve your problem solving power (e.g. with concept maps)
boost your creativity (e.g. with neural creativity)