Tech futurist Paul Saffo writes:

“The Web is moving from being
a place where people access information to a place where people access other
people in an information-rich environment”. 

We find examples of that in sites and communities like Linked In, MySpace and YouTube.

We refer to this phenomenon by a number of names: social media, web 2.0, user- generated
content, social networks.
But not a lot is
said about the difference between the handful of contributors who take the time
to espouse an opinion, and those who are passive consumers of that message. 

The
Guardian Unlimited has suggested a 1% rule: “an emerging rule of
thumb that suggests that if you get a group of 100 people online then one will
create content, 10 will "interact" with it (commenting or offering
improvements) and the other 89 will just view it”.  Microsoft’s Don Dodge offers
a simple
illustration of this phenomenon.

New Influencers rate Amazon reviews, add comments to Yahoo
news stories, post video replies on YouTube. New Influencers see their improvements on the work of others as a form
of self-expression and a way to gain social currency. By interacting with original content, they
validate an author’s expertise. And they
are just as valuable to the social network as content creators.

Consider, too, some statistics from that other community content
generation project, Wikipedia: 50% of all Wikipedia article edits are
done by 0.7% of users, and more than 70% of all articles have been
written by just 1.8% of all users, according to the Church of the
Customer blog (http://customerevangelists.typepad.com/blog/).

Earlier
metrics garnered from community sites suggested that about 80% of
content was produced by 20% of the users, but the growing number of
data points is creating a clearer picture of how Web 2.0 groups need to
think. For instance, a site that demands too much interaction and
content generation from users will see nine out of 10 people just pass
by.