To measure a machines success in imitating human behavior various techniques can be applied. This is commonly known as the Turing test, as developed by Alan Turing (1950). The effectiveness of bots can also be evaluated using a classical Turing test where the quantity and the quality of a bots output is measured and tested on a human test person.
Social network services such as Facebook have introduced certain security techniques to identify bots from humans such as CAPTCHAs (machine unreadabla pictures that can only be parsed by a human user) or automatic detection of massive friending, fake profile names and other unregular behavior. The effectivness of these measures is limited as Huber, et al. (2009) conlude: Continue reading