You might notice that most exclusive content you listen to on sites are played through Soundcloud. Bandcamp noticed too, and are now Bandcamp offering "exclusive embeds."
According to the Bandcamp's website, "the exclusive embed feature gives you a way to get your music to that music critic who really gets it wants to write a review of your latest album, and in exchange for an exclusive first-listens to [his or her] magazine's readers."
Users will be able to tweak the player options to limit the length each track can be played, giving more incentive to actually purchase the album in order to listen to it. Many options will be available to Bandcamp Pro subscribers. More info can be found on their website.