The post was about their online Day by Day jukebox, which I had not seen before. You can choose any date ( I think the default is today's date) and see recording from many years in the past available to play online. What a great addition to calendar time in the mornings, music class, math lessons (how many years ago was this recorded, what is the beat, etc.), social studies (time periods in history), etc. Those are just the first ideas that popped into my head. The first recording for today is from 1905.
If using the Day by Day feature is not what works best for you, you can also search by several different methods including by artist, genre, playlist, etc. There is a brief First Time Here review also. This would allow you to use it as more of a unit. For example, we talk about Marian Anderson with Black History Month and there are several recordings here by her, so you can let students actually hear her singing.
How could you use this in your classroom?