Wikipedia founder Jimmy Wales was on Bloomberg TV earlier this week to clarify that there has not been a mass exodus of voluntary editors. Wikipedia is still very much driven by the community.
Wales also revealed some interesting numbers about Wikipedia. To maintain Wikipedia, it costs around $10 million per year. The website survives primarily off of donations. So far Wikipedia has over $3 million in donations for the year.
Personally I’m impressed by how little it costs to maintain Wikipedia. On a per day basis, it costs about $27,397.26 to keep Wikipedia running.
What about some of the other top websites? As a comparison, YouTube costs about $2 million per day in just storage and bandwidth. Facebook most likely costs close to $300,000 per day considering that they are hosting 10 billion photos. In 2007 and early 2008, Facebook spent around $67 million on rackable servers. Facebook most likely spends $500 million per year between servers, employee salaries, infrastructure, office space, and other miscellaneous costs.
Below is a video of the interview [via BusinessInsider]:
In actuality, because the Mediawiki software renders pages that are easily cached and serve up mostly text (certainly not video or pages and pages of images), it only costs about $1.2 million per year to physically sustain Wikipedia with bandwidth and servers, including the salaries of about 3 developers. This information is all available in the legal Form 990 document that the Wikimedia Foundation is required to file.
Where is the rest of the $10 million budget going? Mostly to salaries of a bloated staff of 35 who sit back and watch the 99.5% of the work that is being performed by unpaid volunteers. Also, the Foundation tucks away between $1 million and $2 million into a bank savings account for a rainy day in the future.
The other firms you cite (YouTube and Facebook) cost more because those companies are trying to ramp up to a state of profitability. It costs money to make money. Wikipedia has no such profitability incentive, so that's why costs are kept low.
I run a site with over 50,000 pages, and over 1,200 unique visitors per day. It costs 61 cents per day to run. Do the math.