In every popular album there always seem to be one or two songs that get the vast majority of attention, no matter the relative quality of the other songs. Google, for whatever reason, has decided to give this phenomenon a bit of visual representation. Head on over to the Google Play Store and click "music" (not the Google Play Music player interface), then pick any of the various albums featured on the front page. You'll see a new column in the track listing, ranking each song in popularity, presumably in relation to the others on the same page.
Oddly, some albums seem to be excluded, multi-artist compilations and extended plays in particular. This feature wasn't on the web version of the Play Store as recently as last week - check the image from this deal post.
The distinction between the most played songs and the least isn't extremely helpful - it's only got a four-dot ranking system (see recent changes to Google's web search for more dot-based UI elements). But I suppose it could be handy if you're looking for an artist's signature song, especially if you're only interested in buying individual tracks.
We haven't seen this element show up on phones or tablets yet, and it may not ever come to that. The mobile version of the Play Store has more stringent space requirements and often omits portions of the web listings.
- Philipp Schuster