Seems like this article plays a bit loose with the facts. Apache Hadoop and MapReduce are based on Google white papers, but Google didn't actually develop either. And is it that Google couldn't afford Oracle software, or they knew they could build something better?
However, the main thrust is valid: the same data that is valuable to Facebook and Google (and their advertisers) is valuable to the NSA.
One of the core principles of free software (as in the free software foundation) is no restrictions on the use or distribution of that software. This also means that if you release a piece of software under a license that prevents, say, arms manufacturers, dictatorships, or the NSA from using it, it is not really a free software licence.
If we are dealing with an organization that routinely lies to congress, how much respect do you think they give the restrictions you place in some text at the start of your source code?
Yep indeed the likes of Google/Facebook/Yahoo open source technologies have made it much easier for the government to create the tools needed to sift through terabytes of data, yet even if Hadoop/Map Reduce etc... were closed source I'm sure the big G would have come up with their own solution.
However, the main thrust is valid: the same data that is valuable to Facebook and Google (and their advertisers) is valuable to the NSA.