First, take a look at “Wikihistory” by Desmond Warzel. It’s very short, and is presented as a log of a forum thread rather than a literal series of posts, but it captures the idea really well.
Then, browse the first few posts of one of the following blogs:
There’s the @wowt2 Twitter account that live-tweeted a version of War of the Worlds and the “invasion plan” they used to produce it.
Welcome to Nightvale is a well-known fiction podcast/internet radio anthology series.
@lonelygirl15 is a now-classic hoax narrative told through webcam confessional videos on early Youtube, and of course Marble Hornets.
Consider how each form of each of these creates opportunities for and shapes contours of narrative: plot, character, audience interaction. In addition, try to make a mental account of all the production tools you would need to create something like each of these yourself.