Table 1. Categorization of Internet bots according to the intended effect of their operations and the kind of activities they perform, including some familiar examples for each type.

	Benevolent	Malevolent
Collect information	Web crawlers Bots used by researchers	Spam bots that collect e-mail addresses Facebook bots that collect private information
Execute actions	Anti-vandalism bots on Wikipedia Censoring and moderating bots on chats and forums	Auction-site bots High-frequency trading algorithms Gaming bots DDoS attack bots Viruses and worms Clickfraud bots that increase views of online ads and YouTube videos
Generate content	Editing bots on Wikipedia Twitter bots that create alerts or provide content aggregation	Spam bots that disseminate ads Bot farms that write positive reviews and boost ratings on Apple App Store, YouTube, etc.
Emulate humans	Customer service bots @DeepDrumpf and poet-writing bots on Twitter AI bots, e.g. IBM’s Watson	Social bots involved in astroturfing on Twitter Social bots on the cheater dating site Ashley Madison