After announcing that the Xbox One wouldn't have backwards compatibility for Xbox 360 games, many 360 owners had to choose to say goodbye to their Xbox 360 games collection or hold on to their outdated console just to play them.
At the time, there was absolutely no hope for backwards compatibility - it seemed like Microsoft were very sure backwards compatibility would never come to the Xbox One and it was a feature that would take a lot of resources that could be better spent on developing other experiences.
Strangely though, Microsoft recently announced at E3 that the Xbox One will be getting backwards compatibility in a future update for the console. This will mean that Xbox One owners will be able to play a variety of Xbox 360 games on the One. There's a chance that not all games will work on the Xbox One but Microsoft are working hard to ensure that as many Xbox 360 games as possible can be played on the Xbox One.
Not only will the Xbox One get backwards compatibility, but Xbox are adding a feature that will bring up the Xbox 360 guide menu within the Xbox One OS. In a sense, the Xbox One will be simulating the Xbox 360 software on top of the Xbox One.
When the backwards compatibility feature is added to the Xbox One, only 100 games will be supported, and it will be at the publisher's discretion to greenlight their games to be supported by the Xbox One's backwards compatibility feature.