Wikipedia
Influenzanet is a syndromic surveillance system that monitors the activity of influenza-like illness (ILI) with the help of volunteers via the Internet. This innovative surveillance system is based on the voluntary online participation of the population who, on a weekly basis, respond to an internet questionnaire about flu symptoms.
During the winter 2003/2004 season, the Netherlands and Belgium launched the first Influenzanet - De Grote Griepmeting - which attracted over 30,000 participants in the first year. The Dutch Great Influenza Survey has been carried out yearly since then. It was implemented in Portugal for the 2005/2006 season; this was followed by the Italians with Influweb in 2008, and then by the French version called GrippeNet in 2012.
With the threat of a new pandemic influenza, three other countries joined this project in 2009, with the implementation of Gripenet Brazile, in Brasil; Reporta in Mexico; and the Flusurvey in the United Kingdom. In Australia, a comparable project called Flutracking started in 2006 with 400 "Flutrackers" completing a 10 - 15 second online survey about flu-like symptoms each week has over 8,000 weekly participants in 2010.