I read about Spaced repetition yesterday and have been using a site called memrise to help me with my vocabulary. So far I have learned 50 new words in a span of two days, which is incredible for me. But at the same time I'm worried that I won't be able to retain these new words for very long. So I was wondering if anyone has had success with this technique, and is it possible to learn around 2000-3000 words in the span of 3-5 months?