Utility bots solve a user's problem, whatever that may be, via a user-prompted transaction. The most obvious example is a shopping bot, such as one that helps you order flowers or buy a new jacket. According to a recent HubSpot Research study, 47% of shoppers are open to buying items from a bot. But utility bots are not limited to making purchases. A utility bot could automatically book meetings by scanning your emails or notify you of the payment subscriptions you forgot you were signed up for.
When one dialog invokes another, the Bot Builder adds the new dialog to the top of the dialog stack. The dialog that is on top of the stack is in control of the conversation. Every new message sent by the user will be subject to processing by that dialog until it either closes or redirects to another dialog. When a dialog closes, it's removed from the stack, and the previous dialog in the stack assumes control of the conversation.
“They’re doing things we’re simply not doing in the U.S. Imagine if you were going to start a city from scratch. Rather than having to deal with all the infrastructure created 200 years ago, you could hit the ground running on the latest technology. That’s what China’s doing — they’re accessing markets for the first time through mobile apps and payments.” — Brian Buchwald, CEO of consumer intelligence firm Bomoda
Before you even write a single line of code, it's important to write a functional specification so the development team has a clear idea of what the bot is expected to do. The specification should include a reasonably comprehensive list of user inputs and expected bot responses in various knowledge domains. This living document will be an invaluable guide for developing and testing your bot.
The classic historic early chatbots are ELIZA (1966) and PARRY (1972). More recent notable programs include A.L.I.C.E., Jabberwacky and D.U.D.E (Agence Nationale de la Recherche and CNRS 2006). While ELIZA and PARRY were used exclusively to simulate typed conversation, many chatbots now include functional features such as games and web searching abilities. In 1984, a book called The Policeman's Beard is Half Constructed was published, allegedly written by the chatbot Racter (though the program as released would not have been capable of doing so).