The article tells us that:
The reason millions are learning it is simple: it is the language of international business and therefore the key to prosperity. It is not just that Microsoft, Google and Vodafone conduct their business in English; it is the language in which Chinese speak to Brazilians and Germans to Indonesians.
What’s interesting is that the linguistic dynamics between the notion of native and non-native speakers are clearly changing too.
Source: Global English?