Plugin that you will be develop is a plugin that allows user to insert content(analytics code, banner ads, text/php content, etc) in specific areas of the blog.
User can select the position of the content(top, left, etc,pls refer the site below for a detailed description), and the specific pages and areas on the blog (refer to the site below). User can also select which pages the content will not show for more control of the visibility of the content. Each content created must also have a shortcode.
Please refer here for a more detailed description: