A blog post is used to write categorised content on a page. Blog posts contain more plugin information than a text plugin that allows it to be used in conjunction with other plugins such as the Blog Title, Blog List, Blog Post Menu. This information includes published date, thumbnail and category of blog.
Jolojo identifies a Blog Post as a page with the Blog Post plugin on it. You can filter pages in Admin > Page management.
Once a Blog Post (page) has been created, you can add any additional plugins onto the page if you want to.