Sentence:  He is particularly good at creating web robots, which are also called <WSD>bots</WSD>. A <WSD>bot</WSD> is software that searches for certain kinds of websites and then automatically does something — good or bad — on each site. Google uses <WSD>bots</WSD> to search and index websites. 
Meaning of the word marked with <WSD> tags:  A piece of software designed to complete a minor but repetitive task automatically or on command, especially when operating with the appearance of a (human) user profile or account.