How crowd-knowledge dwarfs the obsolete institution of encyclopedia

This is the end of another institution that started with the Industrial Age: news spread a few days ago that the Encyclopedia Britannica stopped its printed edition, having sold only a few thousand copies per year in the last years. It will continue to make its database available online.

encyclopedia britannica 1st edition - 1768

Let's do some fun maths. In 244 years of existence, around 7 million copies of the precious encyclopedia were sold (or, on average 30,000 per year). During that time approximately 17 billion people have been born and became adults (see for example this article of Carl Haub, the specialist in historical demography). Thus on average, there was one copy of the encyclopedia available for 2,500 people.

In 2008 Wikipedia saw 680 million visitors in the year and aims at reaching this level every month by 2015. 14% of internet users (14% of 2 billion = 280 million users) go on the Wikipedia site according to Alexa.com. That's one person for 22 living people, or probably approximately one person for 15 adults.

The English version of Wikipedia ONLY contains 50 times more words than the latest Encyclopedia Britannica, or 2 billion words, in roughly 4 million articles (the Encyclopedia Britannica boasts 65,000 articles).

The Encyclopedia Britannica counts less than 5,000 contributors; whereas more than 300,000 editors edit some part of Wikipedia every month.

Crowd-knowledge is here, orders of magnitude more powerful than centralized edition of a paper encyclopedia. In less than a decade, the institution of the encyclopedia has been toppled and made obsolete.

Who said the Fourth Revolution wasn't here?