Breakthecharts itself is a perfect example of this.
We're giving out a free resource to upcoming indie artists. In turn, this whole site goes viral for free because everyone shares it with their friends.
In turn, it drives traffic to our Page builder platform called ListenToThis.io
And the stratergy is so effective. We get 1000s of paying users by doing this. And it's FREE traffic.
Other producers will remix your song, and ultimately it will bring listeners to your original song as well.
I describe this method in more detail on this post here.
For Example, did you remember the Seeb Remix of 'I took a pill in ibiza' ?
Amongst many other popular remixes, this one was more popular than the original song itself, but it did help Mike Posner to grow as an artist BIG time!