I'm rereading Understanding Media again. I last read it (for the 2nd or 3rd time) when the web was new. Something hit me in the first chapter that didn't mean as much to me last time: the content for any medium is other media.
The example McLuhan gives is that the content of the printed word is the written word, the content of the written word is speech, and the content of speech is thought.
So... what is facebook ? Medium or content ?
I came up with this so far: the content of the web is the internet, and the content of the internet is the written word and perhaps electronic communication along the lines of the telegraph.
So is facebook 'content' on the web, or is a new medium itself that contains the web ?