T-mobile used to do this in Germany until earlier this month. In their FAQ [1], they state that the following in spotify count against customers' data plan: videos, album covers, sharing, and Spotify's "discovery" feature. They add a flat 100MB to the data plan to cover that. Note that the streaming of music is not included, so it doesn't count towards data usage.

They stopped offering this to new customers on August 2nd, 2016.

[1] https://www.telekom.de/hilfe/mobilfunk-mobiles-internet/mobi... (in German)