bot-net
Official IAB definition:
"A group of automated agents generating invalid clicks using programmed techniques to simulate random-appearing human activity. Bot-Nets generate a form of click fraud. This type of activity may be very difficult to detect through standard filtration techniques, i.e., they may require very advanced data analyses for detection. Certain click fraud agents, including automated agents, avoid outlier activity; therefore outlier analysis is generally insufficient to detect these sophisticated actors."
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