When I am free writing from brainstorming and prompts I sometimes get confused as to whether I am writing a blog post or an article. They are similar, or can be, and the lines of definition are blurry and vague. I can’t answer the question exactly, but I do have a current option that I am using now as a guideline:
Blog posts are more personal; they center on personal experience, opinion; they are written in a style that is more interactive by engaging your readership. Blogs are chatty. Articles on the other hand, are informational, centered less on personal knowledge and more on legitimate research. Articles fit into established formulas and can be written to specific templates. Blog posts can have structure, but it isn’t required; articles need to be structured. You can get away with writing a blog post that lacks a main point and supporting points, but an article needs these things. Blog posts can be anything including pictures, links, video, text, or any combination. An article must have text and the other things have to be relevant in the supporting role. A blog post might be commentary on an article or someone else’s blog post whereas an article would be more of a critical review.
You will find your own definition as you write them both, but maybe this brief summary will help you determine where to post the stuff you are writing.