Ms. Dewey is a Viral Marketing campaign started by Microsoft in October 2006. It also refers to the character of the same name, who is the campaign’s main subject. The Ms. Dewey website is an Adobe  flash-based experimental interface for Live search. The interface features a modern-looking cityscape as a backdrop with the character on the left side, while the search results appear on the right. The cityscape backdrop changes depending on the time of day.

Developed by advertising agency Mcann-Ericsson San Francisco and interactive production firm EVB, Ms. Dewey appears to be an interactive search assistant who audibly comments on searched keywords in her own style and makes random actions when idle, including taking props from behind her desk. The responses actually consist of about 600 video clips recorded over a period of three days.

Microsoft is not overtly marketing the website, and appears to be relying on media coverage to draw users in. Janina Gavankar plays the role of the Ms. Dewey character

Source: Wikipedia