After student's complete their interest inventor, initial assessment exam, and start reading, their home page will become populated with appropriate books and 'if you liked....' recommendations (along with a host of other browsable book options). The book titles will reflect books that are within 2 grade levels (up and down) of their current reading level.
Student's can also search and browse books based on subject and theme. See the attached document for a visual guide on finding books for K-2 students.