Back in March, Apple reached a deal with Dubset to make sure sampled artists in remixes and DJ mixes on its music service were properly compensated. Last week, Spotify did the same, inking an agreement to leverage Dubset's MixBANK distribution platform to ensure that both the artists creating the mixes and those being sampled receive the royalties they're due. The MixBANK system checks an uploaded track for copyrighted material before getting permission for its use from the correct label and/or publisher.
In terms of content, the deal means that Spotify users will get access to radio shows and individual tracks that didn't previously clear the licensing hurdle. What's more, it means that users will be able to upload any tracks that they create à la SoundCloud. The deal was just announced a few days ago, so there's no word on when the Spotify's remix library will start adding new material.