Google revealed that it had mistakenly collected information about Internet sites people had visited on public Wi-Fi networks.

The admission came from Google engineering head Alan Eustace in the form of a blog post. In the statement, Google said that it had been unknowingly gathering the personal data for over three years through its Street View photo-mapping feature. The discovery was made during internal investigation resulting from earlier concerns by German regulators over the issue. Two weeks ago, Google told European officials that, while it did collect data from Wi-Fi services for location technologies, it did not save private user data. In yesterday's announcement, however, Google admitted that these claims were actually incorrect.

An estimated 600 gigabytes of personal data had apparently been collected because of a software error from 2006. Google Street View vehicles caught bits of information from unsecured or public Wi-Fi networks in both Europe and the United States, as well as around 30 other countries where Street View is used.
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In my opinion google should had at least checked their systems frequently so that they will be able to detect the fault in its system. Google must had also asked the permission to the countries so that other relevant information which also gets included in the system is usable or not.Google in order for them to be on the save side can use the Internet Service Provider (ISP) as a defendent as its the ISP which provides the information captured on the google software. In this example Google could sue the ISP as they provide google with information which is not needed by them.