Microsoft's move to support backward compatibility is just one of the reasons why it has gained huge momentum during the past year. Consumers like more games to play, and this is just one way of significantly increasing the library volume.
In an effort to further market its backward compatibility efforts, Microsoft has begun branding Xbox 360 games as playable on Xbox One. This has arrived on virtually all supported titles, ranging from Fallout 3 to Doom 3, as seen below:
There appear to be at least two configurations for how games advertise this support. Nonetheless, this move has required some investment on Microsoft's part, and it appears that it believes it's well worth it.
Microsoft most recently added Skate 3, LIMBO, and The Orange Box to its list of supported titles.