2010 SIRI: Though Siri is considered colloquially to be a virtual assistant rather than a conversational bot, it was built off the same technologies and paved the way for all later AI bots and PAs. Siri is an intelligent personal assistant with a natural language UI to respond to questions and perform web-based service requests. Siri was part of apples IOS.
ELIZA's key method of operation (copied by chatbot designers ever since) involves the recognition of clue words or phrases in the input, and the output of corresponding pre-prepared or pre-programmed responses that can move the conversation forward in an apparently meaningful way (e.g. by responding to any input that contains the word 'MOTHER' with 'TELL ME MORE ABOUT YOUR FAMILY'). Thus an illusion of understanding is generated, even though the processing involved has been merely superficial. ELIZA showed that such an illusion is surprisingly easy to generate, because human judges are so ready to give the benefit of the doubt when conversational responses are capable of being interpreted as "intelligent".