Spotify has begun letting brands sponsor the most popular playlists curated by the music streaming service, offering advertisers a way to match music with a message. Sponsored Playlists, as they're called, match a marketer with a playlist that lines up with a certain audience they have in mind based on campaign objectives. In a blog post today announcing the new offering, Spotify said it will work with advertisers to drive streams to a playlist during the sponsorship through native promotion, brand marketing and social media.