title: Data set for recommendation system
body: <p>I want to create own simple recommendation system, about books. But there are some problems - it's impossible (at least, very hard) for one person to organize training data set for algorithms. </p>
  
  <p>So, are there any free data sets or quizzes with information about people's votes, which books and how much they like?</p>
  
  <p>Second question is about book's parameters. For some item-based predictions is really must have to use book's ratings (e.g. language, average length of words, average number of words in paragraph, i have counted about 30 parameters like those) and their weights (for example, book's language is rated in 1 point, and average length of words in 0.314). So, are there any prepared information about that? </p>
  
  <p>In fact, if i got an answer for first question, i could find solution for second question, but i am sure, that needed information exists.</p>
  
  <p>Also, i am reading Recommender Systems Handbook, it gives full information (with references), but it is hard to read. Can you advise some extra books in this case?</p>