JUDY WOODRUFF:

Almost all of us have wondered at one point or another about the taxes we pay: Where does the money go?

Former Microsoft CEO Steve Ballmer not only wondered. He decided to make the information available in the form of a new public research tool.

Last week, Ballmer launched USAFacts, an interactive Web site listing revenues and expenditures at all levels of government federal, state and local, all of it free to the public in digestible, searchable form.

I spoke yesterday with Mr. Ballmer, who is also the owner of the Los Angeles Clippers basketball team, about his latest venture, and I started by asking why he wanted to do this.