The concept of smart mirrors truly became popular as a do it yourself (DIY) type of project and still is mainly such a project. That Microsoft as late as 2016 decided to publicly release the details on their smart mirror project for people to build their own rather than commercialize the project are a good indicator that smart mirrors will continue to be a DIY project for some time.
The most known project on smart mirrors is done by Michael Teeuw. His project was among the first to embrace the idea of using a RPI to power an informative mirror. His project is also featured on the official raspberry pi homepage. He has created tutorials on how to physically build the mirror, as well as providing a community-driven open source framework for creating a module-based interface called MagicMirror2. This framework makes it easy to customize the interface with interchangeable modules that can be created by anyone. Examples of existing modules are: weather, news, time or daily comic strip. I will be extending this framework by writing my own modules that will be responsible for the intelligence in the mirror.