This lernu! service will help you improve your knowledge of Esperanto words. You'll learn new words and find out how to use them. Every day, a new Esperanto word will appear on this page with explanations and examples of its use. So that you don't have to visit the page every single day, we recommend that you subscribe to this service. In your profile you can indicate that the new word should be sent to your inbox every day.
There are more explanations about that here.