How many will be affected by #WikipediaBlackout? 100+ million.

The #WikipediaBlackout just started. One question that keeps coming up is, “How many people will it affect?” Let’s put on our stat-nerd hat and build a reasonable estimate.

First off, if we want to put this in human terms, we need to think about people and not Page Views or one of the other metrics out there. One source for that is comScore, which has released fairly recent global data for November 2011 based on its panel of 2 million internet users.

Since the blackout itself is only on English Wikipedia, let’s start there. comScore estimates that each month 236 million people (or “Unique Visitors”) come to the English Wikipedia globally from a browser on a computer. Of that, comScore estimates 25 million people daily (or “Average Daily Visitors”). That’s a good start for an estimate of how many people will encounter the blackout. But we have to consider a few things:

• comScore’s panel excludes internet access from schools, internet cafes, and anyone under the age of 15. It’s also focused on countries with well-developed online advertising markets, so may have less complete data for many countries. For example, Wikipedia’s server logs show it actually delivers about triple the page views that comScore’s panel reports. Let’s be conservative and double comScore’s estimate to fill in the gaps in its coverage, which gets us up to 50 million people.
• The comScore daily average is across 7 days a week, and Wikipedia traffic is typically lower on weekends. So let’s add another 20% for a Wednesday, getting us up to 60 million people.
• comScore specifically excludes mobile traffic, which is probably up to 15%+ of total Wikipedia traffic. To ensure emergency use, mobile users to English Wikipedia are simply seeing a banner. That gets us up to let’s say 70 million people.
• With all the press coverage, we may see an uptick in visitors. Let’s say 10%.

That gets up to an estimate of 75 million people affected by the English Wikipedia blackout and mobile protest.

A few other language Wikipedia communities are supporting the English Wikipedia community with banners or other notices, including the Japanese (5.8 million daily visitors according to comScore), Spanish (5.5 million),  Russian (4.2 million), German (3.7 million), Portuguese (1.7 million), Italian (1.3 million), Arabic (960k), Chinese (900k), Vietnamese (325k), and Korean (175k), plus other language Wikipedias that comScore doesn’t break out including Polish, Norwegian, Swedish, Catalan, Czech, and Ukrainian. That adds up to another 25 million, and if you apply the same adjustments as above gets us up to another estimated 75 million people affected through banners and notices on other language versions of Wikipedia.

So, a reasonable estimate suggests that 150 million people will see the various Wikipedia actions globally.  Wow.

-s

UPDATED 7:45a Pacific time to include more language versions of Wikipedia which I didn’t know would be showing banners or other notices.  That’s another 9mm comScore daily visitors which with adjustments to fill gaps in comScore coverage suggests 75 million people will see banners (up from earlier estimate of 45 million).  That increases overall estimate to 150 million (up from earlier estimate of 120 million).

PS — Below is some detail of the raw comScore data for a few different countries. To fill the above-mentioned gaps in comScore’s coverage, you need to triple these raw numbers to get a good estimate of actual visitors.

• In the U.S., comScore estimated 78 million people visit the English Wikipedia a month (about 42% of U.S. internet users). That works out to about 9.5 million people on an average day.
• In the U.K., comScore estimated 18 million people visit the English Wikipedia a month (about 49% of internet users). That works out to about 2.8 million people a day.
• In Canada, comScore estimated 13 million people visit the English Wikipedia a month (about 54% of internet users). That works out to about 2.1 million people a day.
• In Australia, comScore estimated 5.5 million people visit the English Wikipedia a month (about 40% of internet users). That works out to about 700k people a day.
• In Germany, comScore estimated 5.8 million people visit the English Wikipedia a month (about 11% of internet users). That works out to about 400k people a day. The German Wikipedia is also showing a banner so that adds 24 million monthly visitors (48% of internet users), or 3.2 million per day who will see something blackout-related.
• In France, comScore estimated 4 million people visit the English Wikipedia a month (about 10% of internet users). That works out to about 250k people a day.
• In Russia, comScore estimated 3 million people visit the English Wikipedia a month (about 6% of internet users). That works out to about 200k people a day seeing the blackout. The Russian Wikipedia is also showing a banner so that adds 21 million monthly visitors (40% of internet users), or 2.6 million per day who will see something blackout-related.
• In India, comScore estimated 16 million people visit the English Wikipedia a month (about 35% of internet users). That works out to about 1.5 million people a day.
• In Malaysia, comScore estimated 3 million people visit the English Wikipedia a month (about 27% of internet users). That works out to about 285k people a day.
• In the Netherlands, comScore estimated 2.7 million people visit the English Wikipedia a month (about 23% of internet users). That works out to about 253k people a day. The Dutch Wikipedia is also showing a banner but comScore doesn’t yet track it separately.
• In China, comScore estimated 2.9 million people visit the English Wikipedia a month (about 1% of internet users). That works out to about 230k people a day. The Chinese Wikipedia is also showing a banner so that adds 4.8 million monthly visitors (1.4% of internet users), or 346k per day who will see something blackout-related.
• In Turkey, comScore estimated 2.9 million people visit the English Wikipedia a month (about 12% of internet users). That works out to about 195k people a day.
• In Spain, comScore estimated 2.4 million people visit the English Wikipedia a month (about 11% of internet users). That works out to about 160k people a day. The Spanish Wikipedia is also showing a banner so that adds 9.4 million monthly visitors (43% of internet users), or 1 million per day who will see something blackout-related. The Catalan Wikipedia is also showing a banner but comScore doesn’t yet track it separately.
• In New Zealand, comScore estimated 1.2 million people visit the English Wikipedia a month (about 42% of internet users). That works out to about 150k people a day.
• In Japan, comScore estimated 2.6 million people visit the English Wikipedia a month (about 3.5% of internet users). That works out to about 140k people a day. The Japanese Wikipedia is also showing a banner so that adds 39 million monthly visitors (54% of internet users), or 5.6 million per day who will see something blackout-related.
• In Brazil, comScore estimated 2.4 million people visit the English Wikipedia a month (about 5% of internet users). That works out to about 140k people a day. The Portuguese Wikipedia is also showing a banner so that adds 16.5 million monthly visitors (36% of internet users), or 1.5 million per day who will see something blackout-related.
• In South Africa, comScore estimated 1.5 million people visit the English Wikipedia a month (about 22% of internet users). That works out to about 125k people a day.
• In Italy, comScore estimated 2.1 million people visit the English Wikipedia a month (about 9% of internet users). That works out to about 125k people a day. The Italian Wikipedia is also showing an interstitial and banner so that adds 10 million monthly visitors (42% of internet users), or 1.1 million per day who will see something blackout-related.
• In Singapore, comScore estimated 1 million people visit the English Wikipedia a month (about 35% of internet users). That works out to about 125k people a day.
• In Sweden, comScore estimated 1.3 million people visit the English Wikipedia a month (about 21% of internet users). That works out to about 115k people a day. The Swedish Wikipedia is showing a banner but comScore doesn’t track it separately.
• In Mexico, comScore estimated 2 million people visit the English Wikipedia a month (about 9% of internet users). That works out to about 110k people a day. The Spanish Wikipedia is also showing a banner so that adds 10 million monthly visitors (47% of internet users), or 1.2 million per day who will see something blackout-related.

Attached is a detailed worksheet with more comScore data for those data nerds who’d like to dig in. I’ll update this post as more info becomes available.