Facebook social graph.
How many people in the world use Photoshop? What about Illustrator, Final Cut, Maya, or any other popular media authoring application? How would we make even most approximate estimate? While Adobe, Autodesk, and Apple know how many copies of their software products they sell every quarter, this information is never released. But even if it was, the proportion of people who buy their software vs. all other users is so small that the sales numbers would not help us much.
We know so little about contemporary culture. Its flows, evolutionary mechanisms, patterns of dissemination, reuse, copying, and material bases (such as the number of copies of top software applications which enable it) are not visible to us. It is as though we have our eyes stuck very close to a map - we see few points, but unable to zoom out and see the larger picture.
One area where numbers and maps do exist is the usage of social networks. We know how many blogs are active, how many people use Twitter, how many photos are uploaded to Facebook every month (this number is already over 10 billion); YouTube gives us graphs showing the number of views for every video over time; Google Insights for Search allows us to study the popularity of any search term across time (since 2004) and territories. This is something, but its still limited. It is as though we zoomed out but are only able to see the overall contours on the map defining the areas - but not the details inside. And when some details are made available, they follow the rule of majority - we are told which topics, search terms, videos which are "most popular." These are the tips of the tips of the iceberg, and they are not very interesting. (For example, entering "top searches in the U.S. over 30 days" into Google Insights for Search returns these top items: 1) shoes, 2) samsung, 2) amazon, 4) boots.)
Back to Photoshop. Since late 1990s, I mostly work in cafes - which in Southern California means Starbucks. I am always curious what other people are doing on their computers and tablets around me, and I noticed the following pattern. If I am in a Starbucks and there are at least 10 other people with computers, one of them is using Photoshop. This is an informal observation, and it may only hold for the particular part of San Diego where I leave. But even if the real number is more like 1:20, this is already quite amazing.
What about the places where you live? Did you notice any similar pattern? if we can compare observation, it will give us at least some indication of how many people around the world are engaged in "art" and "design." Would not you want to know this?