We are beginning to see a new interaction paradigm for the web: the Virtual Personal Assistant (VPA). A VPA is task focused: it helps you get things done. You interact with it in natural language, in a conversation. It gets to know you, acts on your behalf, and gets better with time. The VPA paradigm builds on the information and services of the web, with new technical challenges of semantic intent understanding, context awareness, service delegation, and mass personalization.

Siri is a virtual personal assistant for the mobile Internet. Although just in its infancy, Siri can help with some common tasks that human assistants do, such as booking a restaurant, getting tickets to a show, and inviting a friend. We will describe the technology underlying Siri and how it fits in the larger ecosystem of services and data providers. And we will offer a vision of where assistants like Siri are going.