"By some reports, every two days, we now create more content than was created from the beginning of time until 1993. I'm not sure I totally believe that stat, but even if it's an exaggeration by an order of magnitude, we're still talking about a ridiculous amount of content creation every single day."
Twitter, Facebook, blogs, mashups, amature *, fan fiction.
The thing that was missing before the 1990 to 2k time frame was the easy to use avenue anybody could use to distribute content they produced to a mass audience.
Sure there were usenet, ftp, and things before that, which were great at the time, but not exactly the most practical venues or most widely used once the web technologies started to develop. Usenet was good for text, not so much for larger binary stuff, ftp was good for general distribution, but needed to be combined with something else advertise the contents.
It wasn't until the web based avenues started to mature that that things really took off and to my vague recollection it seems like these avenues never really matured until the post 2k time frame so "By some reports, every two days, we now create more content than was created from the beginning of time until 1993." seems completely credible to me.