Google's BigQuery: Promising

I have recently been introduced to Bigquery. It is a service proposed by Google, which allows companies to process large amount of data thanks to Google's wonderful skills. Google indeed is used on a daily basis to scan through an incredibly huge amount of data, in order to propose the best search results to its users. Hence, they are now using this expertise to the corporate world.

Here is a good video showing how it works, and the strengths of Bigquery:

Now there is something that bugs me about it: It is the privacy issue. How Google may assure the privacy of the data it will process?

Also there is another correlated question: How is Google making money out of it? It doesn't seem clear if the service is free or not. But Google is used to propose free services in order to get from users' data to propose keywords.

What do you think about it?