We have characterized different classes of events in terms of evergreens, mayflies and impulses which show topic flux. We use a threshold to cut white noise. Typical time series of examples of the four classes of search patterns are  shown in the figure below.

The average growth and decay rates of the number of uses of a given search term as well as their fluctuations in time will reveal invaluable information concerning the intentions of Internet users. Evergreens appear nearly every day with a high volume which is larger than the defined threshold.

Endogenous impulses can occur due to cultural, seasonal and word-of-mouth recommendations. Exogenous impulses are caused by positive or negative news stories. Our goal is to exploit the fruits of our significant research investment by combining our expertise in probing the dynamics of interaction, both endogenous and exogenous, of people at the origin of the socio-economic organization of society.

The figure shows the volume of certain search terms in the course of time. After a major disaster, such as a tsunami, one can observe an impulsive surge of interest concerning this term, which then relaxes back in time according to a time-dependent 'response function'. This relaxation is reminiscent of the time relaxation observed for other social phenomena. The time series of the number of uses of a given search term tends to grow in the course of time until a given event such as Christmas occurs and then abruptly drops off after the event.