The study was conducted by Keynote Systems, a San Mateo, Calif., company that tests the performance of Internet technologies and sells monitoring services to clients.

Keynote Systems, which analyzes Web site performance, reported that most tax sites had shown remarkable stability and speed.

In the last 15 years Keynote Systems has grown organically and through a series of acquisitions.

Keynote Systems is a Silicon Valley, California Company that employs approximately 500 people and has revenue of $103.0 million in fiscal year 2011.

Usablenet powers the world's fastest mobile commerce sites, according to studies from Keynote Systems.

The world's fastest content delivery network (as rated by Keynote Systems)

He is currently Director of Privacy Services at Keynote Systems.

By early 2004, Umang Gupta, the chairman and chief executive of Keynote Systems, had acquired 10 companies since the Internet bust.

That was the province of a study by Keynote Systems, a provider of Web site performance measurement.

Keynote DeviceAnywhere, a subsidiary of Keynote Systems, Inc.