From their Press Release:
In 2012, Angry Robot Books began partnering with Indie bookshops in the UK to offer free ebook bundling via the Clonefiles initiative. Angry Robot has been giving DRM-free ebook editions free as companions to all physical books sold at participating Clonefiles stores. Now, Clonefiles is coming to North America.
With BitLit as a fulfillment partner, Angry Robot has teamed up with leading independent bookstores McLean and Eakin Books and Prairie Lights Books to offer free ebook editions with all physical copies of Angry Robot Books sold at these two stores.
Angry Robot have always been champions of DRM-free eBook publishing and are been eager to experiment with new business and distribution models. A dual-format offering for Indies is a natural extension of Angry Robot’s customer-first ethos and a great way for Angry Robot to show some love for the USA’s fantastic Indie bookshop scene.
Upon purchase of physical book, customers will receive information on how to download the free BitLit app and use it to claim their free ebook edition of Angry Robot Books.
As someone who loves owning physical books but enjoys the convenience of ebooks, I'd like to see more SF/F publisher pick up on this idea.