Microsoft bought the domain for its rumoured Surface Phone
Buying the domain does not indicate that Microsoft wants to do anything more than own the domain. However, the company is rumoured to be working on a phone with the same name.
Microsoft also boughtSurfaceCar.com which now redirects to the Surface section of the website.
One suggestion is that Microsoft is now shifting all of its products over to the Surface brand, which it introduced in 2012. According to reports, Microsoft is planning the last Lumia device in the coming months and it could transition over to Surface.
This theory is interesting: The Surface Phone, in whatever form, could be misnamed. Instead of being a new device, it could just be whatever Lumia Microsoft was planning with a new name.