A blogger is someone, who writes articles on various topics according to a specific requirement of his audience. Blogger does not plant his all ideas into a blog post. He just follows some rules of blogging and then he writes the articles for a specific category of public, who are interested to read articles on that particular topic.
And a writer is person, who writes about anything whatever he wants and follows his own style of writing. He just writes it. He puts his ideas into an article and he does not care about how many words this article should have and does not care about the style of writing. The writer only writes and uses his wisdom, imagination, dreams, ideas and experiences to write and write only.