The media world is changing fast. The latest anecdotal evidence of that: TV star Keith Olbermann left his post at MSNBC this weekend with zero explanation, yet he hasn't lost his access to the public's ear. Olbermann just Tweeted to his 200,000 fans on Twitter.

Specifically, he Tweeted that he's going to Tweet. At 8 PM EST tonight. Presumably about why he left his show so abruptly. Was it because of the Comcast/NBC merger the day before? Was it not that at all, but rather longer-running tensions between the star and management? We'll be able to hear it directly from the horse's mouth in just over 5 hours. In 140 character chunks.

In some ways this is a small thing. Like Rick Sanchez building an audience on Twitter as @RickSanchezCNN and then getting fired. Or numerous mainstream media publications starting Tumblr blogs of curated found content from around the web. Or SpongeBob SquarePants launching new episodes first on Facebook, before TV.

None of these are huge news in and of themselves, but together they paint a picture of dramatic change. Change away from a past where huge audiences sat passively and consumed a small quantity of time-restricted, highly-produced streams of content, delivered through a limited number of distribution channels that were secured by conglomerates at great cost. The days in which there was just one media game in town are fading fast, pushed into history one Tweet at a time.