Data data data! Photo by Flickr user Antonio Roberts, used under a Creative Commons license.

Ladies and gentlemen. The Name That Data challenge in front of you may be the most important one yet, for it gets at the very heart of what it means to name data.

The first chart is a Google Ngram plot of two distinct but closely related two-word phrases, which we'll call the "red term" and the "blue term." The chart plots their relative frequency in English-language books from 1800 to 2008, the last year for which Google provides Ngram data. As you can see, historically the red term has been used more frequently, but starting in the late 20th century it began to lose ground to the blue term. Now, the usage of the two is very similar.

The second chart plots the same two terms, but this time it's their frequency in Google searches since 2004. In this realm the blue term is king and has been widening its advantage over the red term since about 2007.

The task before you: identify the two phrases. As you know by now, you can comment below, email me, or tweet at me using the hashtag #NameThatData.

Hint: neither one of the phrases is YOLO.