Google has responded to a letter from the House Committee on Energy and Commerce which wrote asking what action the company had taken over its harvesting of private Wi-Fi data.
The online advertising and search giant said it was unable to tell the committee how many networks it had stored payload data from, or how many US consumers or households were affected.
It said it began mounting antennas to its Street View cars to collect Wi-Fi data in late 2007 and they were fitted on all of Google's Street View cars by early 2008. The collection ended in May 2010 as the privacy row deepened.
The cars collected Wi-Fi data including MAC addresses, SSID, signal strength, data rate, channel of broadcast and encryption method. It was, teh firm said, collected in order to improve the accuracy of location-based services. Google stressed again that the collection of payload data was a mistake and that because the system changed channels five times a second, and the car was moving, it was unlikely to have collected more than small fragments.
But Google said it had not conducted any analysis to find out if this was true. In fact the payload data has only been accessed twice - once by the engineer who wrote the code and once as part of the investigation by Google.
The letter, available here, said Google had already deleted data collected in Ireland, Denmark and Austria at the request of data protection authorities in those countries, but it has kept the data in the US because of pending legal action.
Google said it did not believe it had broken any laws by accessing open networks. But the letter said: "We emphasize that being lawful and being the right thing to do are two different things, and that collecting payload data was a mistake for which we are profoundly sorry."
It said it was reviewing data collection for all its services to stop similar problems happening again.
In total Google collected some 600GB of network data from 30 countries. ®