RIPE NCC, one of five Regional Internet Registries (RIRs), does a great job with collecting data of the network traffic during the event. In collaboration with the European Internet Exchange Association (Euro-IX) they follow the Internet Exchange Point (IXP) traffic during the championship.
Two examples from their research. The following graphs shows in red the traffic of the match day and the same day of the week in the weeks before as grey lines. The game times are indicated as grey rectangles in the background.
The Netherlands – Spain
The traffic volume during the Netherlands-Spain game differs 256 Terabytes to the week before!
Cameroon – Brazil
These traffic drops makes you wonder how much energy was saved by these games.
More information about the network traffic can be found at RIPE NCC and more information will follow during the World Cup.