The map is based on the Open Source Index, which was put together by researchers at Georgia Tech. Says redhat:
The OSI is a measure of the open source activity and environment in 75 countries. Each country is given a score based on its policies, practices, and other data in the fields of Government, Industry, and Community.Clicking on a country will show its overal open source ranking among the 75 countries rated, as well as its ranking in government, industry, and community factors. Government factors include official policies; industry factors include "the number of registered OSS users per capita and internet growth"; and community factors include "the number of applications to the Google summer of code, native language support for GNU/Linux, and number of Internet users per capita."
Click on a country to see the country's rank (1 being the highest, 75 being the lowest) in open source activity. One map shows Activity, which measures the amount of open source happening today. It tends to be made up of concrete factors, such as existing open source and open standards policies and number of OSS users, such as Linux and Google.
You can also see an Environmental map, which is more speculative. Even a country that does not have a high degree of current penetration of open source may have a high number of internet users and information technology patents. These factors may indicate a favorable environment for open source software to take hold.
The number one overall ranking goes to France, followed by Spain, Germany, Australia, Finland, Great Britain, Norway, Estonia, the US, and Denmark. Moldova's 75th best. Out of 75.