Over the past year+ we've been curating and steadily building a handful of playlists on Spotify. These playlists are curated according to our tastes and preferences, and as a result whether or not a song is included is entirely subjective.
Because of the number of submissions we receive, we've partnered with SubmitHub and PlaylistPush to help manage and grow the playlists. We do not take submissions via email, or DMs on social media (whether directly to the band or the members individually).
Both of those services do have associated costs to run campaigns/submit music, and as a partnered curator we do receive a small fee (which ranges from $0.50 - $1.25 per review) for our time and feedback.
100% of what we make from these services is cycled into the marketing budget to continue building these playlists - which just helps everyone in the end!