Short answers, pulled from the story.
Ann Stephens founded PC Data in 1991. Before creating the company, she had served as head researcher for the Software Publishers Association, the trade organization representing American software companies, which gave her direct insight into the industry's data gaps.
PC Data was an American market research and point of sale tracking firm based in Reston, Virginia. It initially tracked retail sales of computer software in the United States, later expanded to include hardware sales, and in 1999 added Internet traffic measurement.
By September 1998, PC Data's coverage of the United States retail software sales market had grown to 80%. The Washington Post had described the firm in 1996 as the preeminent tabulator of facts and figures of the monthly sales of consumer software in the United States.
PC Data closed in March 2001 after two of its major business lines were dismantled simultaneously. The NPD Group acquired its point-of-sale research branch, and a legal settlement with Jupiter Media Matrix over patent infringement forced the company to cease its Internet traffic research, leaving it with no remaining operations.
The NPD Group purchased PC Data's point-of-sale research branch and merged it with its Intelect Market Tracking division. NetValue and ComScore each purchased portions of PC Data's Internet research assets.
PC Data settled a patent infringement dispute with the rival company Jupiter Media Matrix in March 2001. As part of the settlement, PC Data was required to cease its Internet traffic research operations, which it had only launched in 1999.