Network Effects

The essence of Web 2.0 is inversion of control of content production
from large organizations to individuals. With Web 2.0, people can create
content with only a very small initial investment of effort. The
revolution comes in the fact that these small productions are able to
garner real audiences through the web. A television program must have
hundreds of thousands of people viewing it to be profitable. But for a
blogger, or a YouTube video producer, the audience need not be so large
for it to be a worthwhile pursuit. More and more, the media that we
consumed is not produced to be viewed by large audiences, but instead by
small viewerships who are able to feel more connected to their content

This is valuable because it allows content creators to specialize to a
degree that was impractical before Web 2.0. The sorts of niche content
that might interest a potential audience of only a few thousand or even
a few hundred would be practically unpublishable in the past, to say
nothing of the uber-context-specific content on sites like Facebook.
There are surely downsides to this: the lack of exposure to different
persepectives can create communities who are hostile towards anything
different from their own cultural norms. But compare the development of
the Web to an analogous cultural shift, the invention of the printing
press. Certainly the printing press allowed hateful ideologies to more
easily convince many far and wide of their views. But it also gave rise
to a revolution in science; cells of natural philosophers in different
countries and situations all working on a vast array of issues and
collaborating on understanding their results. At its best, Web 2.0 can
do even better.