There was a blog that didn’t admit to being a fictional character, though most ended up thinking it was. The blogger claimed to be a teenaged girl who was dying of some terminal disease, and had a lot of people on edge about her condition. Finally she “died,” but eventually people who tried to find her family announced that she was a fake.
There used to be a blog for Cassie Newton, a character from a couple 7th season episode of Buffy the Vampire Slayer. It was apparantly put together by people working at the studio that made the show. I can’t find it anymore though.
http://www.livejournal.com/community/nayrootoe_rpg/ has a bunch of blogs from just about all the Naruto characters. How fascinatingly pointless.
There’s a lot of journal-based roleplaying games where the players create blogs based on their characters and then post in-game threads to a community. (The player blogs are used for information and much silliness.)
Yeah, there was one of these that purported to be a Harvard Law student but was eventually revealed as a fake, as I recall.
By the way, I’ve thought for a while that, if one were writing a novel (which I’m not), giving a character a blog would make a good substitute for dramatic asides; i.e., a way to let characters speak the unguarded truth.
You could use it for chapter intros and/or extros, or something like that. You could show a lot about a character by showing how they blog. Do they use gramatically correct English? Do they use slang, shorthand, anything like that? Are they unusually cheerful or sappy in their blogs compared to their real character? etc.
Oh, and another set of fictional blogs, several of the characters of the webcomic Can’t Sleep Con Will Eat Me have blogs. The site hasn’t been updated in a while, but the comic’s fairly amusing, and if you’ve ever worked at a sci-fi convention (narrow audience, I understand), it’s HILLARIOUS (also helps me that I know the people that the characters of the webcomic are based on, but eh).