Late one night this past week, I lay in bed after watching Agents of S.H.I.E.L.D.. The current season deals with the fallout that comes of uncontrolled transformation of potential Inhumans into powered Inhumans, and has by now started its adaptation of the "Secret Warriors" story arc from the comics.
While laying there, I wondered that if Inhuman transformation is both uncontrolled and unpredictable (the emerging seasonal villain is Hive, established as a parasite-based group-mind entity, taken form via Inhuman transformation back when this was a Kree bioweapon experiment), then it is inevitable that powered Inhumans will emerge that neither S.H.I.E.L.D. nor HYDRA can control. (Hive is the villainous example.)
Now, consider this: the Marvel Cinematic Universe posits that our real world and the MCU vary, on Earth, only slightly in terms of technological capacity (and those divergences are tightly controlled). That means that the Internet is a thing, and so is all that is within it. Therefore, the concept that not one new Inhuman arises that can't usefully (if ordinarily) use our technology is preposterous.
The MCU, therefore, has to have superpowered bloggers. Of that group, some of them blog as their persona and talk about their doings and beings.
In short, Marvel's being stupid by not having in-character blogs as part of their marketing strategy.
This is where DC has an avenue to eat Marvel's lunch, but they aren't doing it either. Hell, no one with such a potential in their properties is doing it. (This is really stupid, considering DC has fucking Oracle, Barbara Gordon's post-paralysis persona that is a Shadowrun Decker in all but name.)
It's not like this idea is really out there. Alternate-Reality/Augmented-Reality Games has been known to be part of the marketing team toolbag for years, and blogging is just a normie-friendly version of that. The web-only videos that new Battlestar Galactica did was a video-focused version of blogging, so even the normie-friendly ends are not new or radical.
Blogging is cheap. Blogging is easy. Blogging can be used to train or vet new writers into the house style before sending them on to more important writing work in-house. A marketing team working for something like the MCU or DC's TV/film properties and NOT using in-character blogging is doing it WRONG.
Because blogging is cheap and easy, in-character blogging is also something small-timers can do. It's an extension of the revelation that Wikis are superior than print/POD products for the publishing and dissemination of lore (the fictional information that's useful for world-building, and for in-character decision making, but superfluous for most actual story-telling craft decisions). Not all things a character has to say or do will be worth including into your novel, short-story, etc.; using that as marketing fodder via an in-character blog allows you to redeem the time spent writing that by using it to keep audiences engaged between publication releases.
And yes, I intend to follow my own advice.