The original report claims that Worldwide IT spending is forecast to total $3.6 trillion in 2011
. The article, being in the English language, the definition of trillion is short-scale. This means that one Trillion is 1,000,000,000,000 (one million million; 10^12; SI prefix: tera-)
according to Wikipedia.
The confusion comes from the fact that there is a difference between countries that got French-heritage and English-heritage. In French speaking countries, a trillion
is defined as 1,000,000,000,000,000,000 (one million million million; 10^18; SI prefix: exa-
.
There are historical reasons behind this decision.