Harken - Flashcard app using smart repetition to improve your memory
SmartCards+ - Spaced Repetition Software for iOS. Modern, powerful and easy to use.
Instapaper - Instapaper is a simple tool to save web pages for reading later.
Zorbi - Spaced-Repetition Flashcards - Other tools are built by boomers, Zorbi is built by students.
Pocket - When you find something you want to view later, put it in Pocket.
Keep Everything - Light & Fast Web Archiver for iOS, OS X.