I've actually thought of creating a story via actual blog posts before, as I'm sure it's done frequently. I've always wanted to get around to doing something like that, as it'd probably be a ton of fun.
I don't have much of a story yet, but I'm writing along the lines of a world that exists, that the first character, the protagonist, tries to fix (due to either an injustice, a global disaster, a political problem, etc.; I'm not sure yet myself). Something has compelled the protagonist to write about their experiences in an attempt to reach out to someone, immortalizing themselves in memoir. As the story progresses slowly, other character's accounts appear, proceeding to give their own accounts of the events, which are no doubt augmented by their own structures of belief and how they are as people. This would cause conflicting accounts, which would cause the reader to either side with a character interpretation or make one themselves, based on the accounts provided.
I haven't gotten everything planned out yet, but as far as I know, it'd be serialized by "entries" or days that are written in said journals. Some would be stories within stories in order to explore the character, while others may be "non-fictional" accounts of events that transpire. I'm looking to the 1001 Nights and The Prestige for a basic framework to how I'd like to structure it.