Vocabuo is a memory card app utilizing the smart spaced repetition algorithm to aid users in learning Spanish, German, and English. It offers audio, images, explanations, and sentences to help users recall approximately 100 words in 15 minutes. Vocabuo emphasizes the importance of contextual learning, allowing users to learn words through sentences, not just in isolation. Additionally, it provides a vocabulary extractor, which can create practice sets from any text, and supports YouTube integration as well as an in-built browser to broaden the user's vocabulary.