Tumblr launched its first advertising product specifically designed for its mobile apps earlier this year, and now the company has found another way to monetize its offering: sponsored trending blogs. Currently, trending blogs show up under the explore tab of the iOS and Android apps, and soon companies will be able to pay to have their blogs show up among those trending results. The first sponsored blogs will come from companies like Calvin Klein, Delta, Sony Pictures (wholl feature a Daily Bugle blog to tie in to the upcoming Amazing Spider-Man 2), and Fox, which is launching a sponsored blog for the film Devils Due today. Tumblr says this new ad unit will roll out in beta this month, with a full launch planned for January of 2014.