Create a new post within the given blog.

Pass markup to set the post's visual content via PML. Invalid markup returns 400 and the post is not created. Pass expand[]=markup to have the markup returned in the response.

See Creating a blog post in the Blogs Skill for the permitted fields and the publish-state rules. To copy an article in from an RSS/Atom feed or an external page, follow Normalize external HTML for PML and Create a draft in the Import External Blog Post Skill.