Castle TV show has been busy. Richard Castle, fictional character, author, and amateur sleuth, even has his own author bio page on Amazon.
Castle's first novel Heat Wave, made the NY Times best-seller list. As recently as this summer, its paperback version was still there. Heat Wave was reviewed more than 360 times by readers who posted thoughts on Barnes & Noble's site (composite rating is 4 stars out of a possible 5). And the follow-up novel is available for preorder on Amazon in hardcover or Kindle.
What's the marketing point? Well, in a multimedia world, presenting a TV character as a novelist popular enough to get his books into real stores and real best-seller lists is good cross-platform marketing. Posting chapters online to draw fans to the official web site of the TV series (where DVDs of previous seasons are also sold) is good cross-platform marketing.
Giving the "author" Richard Castle his own slightly tongue-in-cheek Facebook page and Twitter account is good cross-platform marketing. Plus these elements encourage engagement and dialogue with fans. No mystery there! The only mystery is who actually wrote the two Castle novels...