[stolio]

That says unsigned artists must register with one of those four services. From their web page, the first one listed (https://www.recordunion.com/) is a digital distribution company that charges under $15/year to interface with an online store on the artist's behalf.

If an artist is signed to a label then it's on the label to have a working relationship with the online stores and streaming services.

[simplexion]

So... they have to pay $15 a year for someone else to upload their music?

[mkr-hn]

This is normal. I think Pandora and Grooveshark are the only services that don't require a distributor for unsigned artists.