There is a chain. There is the World Wide Web, which is a mass indiscriminate content creator. Then you have 4chan, which functions as both an individual content creator on the WWW, and as a giant aggregator. 4chan users aggregate funny pictures they recontextualize from bad advertising, screenshots of incomprehensible dialog in TV shows, the best webcomics, etc. 4chan is a mostly a massive dumping ground filled with garbage, but because of the ephemeral nature of threads, result in only content that frequently gets reposted has a chance to survive the churn. Most people cannot stand this, and stay away. But 4chan is populated by content-addicted denizens, who process, filter and promote good memes. And then turn right around and push this content back out onto the more "respectable" and filtered, less-chaotic sites like Reddit and CheezeBurger Network, Facebook, which are meme-propagating machines in their own right. But they primarily get access to the content that was subjected to the vicious selection process of 4chan to begin with.
I think the process by which 4chan operates in media is far more sophisticated, less centralized, less commercial and (perhaps surprisingly) less cynical than celebrity gossip that is created en-masse for money by large national media corporations for top-down consumption. By the time a meme makes it to facebook it's been largely stripped of its participatory power and becomes a one-way medium, but that's just at the periphery of the meme-propogation, the people that just consume it with their electronic feed tubes. But the process of creating this content before it gets to the edge web is a chaotic, churning process of evolutionary competition, mutation, selection.
This is worthy of study. It is participatory culture in the making, what the creative commons and the free culture movement always wanted. There may not be a lot _fundamentally_ new here, except in the context of the 'net in which it is being created. And the medium shapes the message. The web is a "new place." and there are people in it that are, right now, creating the native language of a place that has never existed before. These are exciting times. I think that the messageboard one day will be recognized for it importannce in the history of the WWW, and the Internet in general.