Well, if not all of them, then most of them! If a writer is lucky enough to secure representation, one of the conditions the agent imposes is, the writer must commit to marketing his or her novel on social media, and with gusto! The theory is, only when ones book has achieved a great deal of notice has the agent a chance of securing a publishing deal. So what does the literary agent actually do to earn his/her 12% commission? I am not a marketeer! I merely write, which these days apparently is not good enough!