Website http://www.scholastic.com/kids/stacks/
This website has several section to explore: Books & Authors, Games, Blogs,Videos and Forum. The Book & Author section has an interactive chart to show different genres of books and then interviews with popular authors. The games section has computer games that are based off of books or ideas in books. The blog section seems to cover different competitions hosted by Scholastic with different companies. I am very interested in the Summer reading competitions. Schools can sign up and compete against other schools or students can sign up as individuals. The videos section are good for engaging student interest in a book. The types of videos featured are book trailers, interviews with authors, series information and celebrity interviews. Here is their book trailer for Thirteen Gifts.
The overall layout of the website is geared toward tweens. I think a tween who is already excited about a book or writer who has a contract with Scholastic would enjoy this website. There is a place to signup and become a member.

Forum

http://community.scholastic.com/reading-buzz-board.html

The forum is a place for members to post about a favorite book or Author like Meg Cabot or Gordan Korman. I think a community forum is a great place for tweens to share the books they are excited about reading. Since this website is owned by Scholastic it is moderated by adults but how well I cannot verify.