The actual display protocol isn't that interesting. The things that matter are connectivity and convenience. You can be in any random network location, as can the desktop, and it will be able to do the connectivity plumbing. On the convenience side it hooks into your Google authentication (blessing or curse) and requires an additional PIN for the connection.

The Chrome extension for viewing lets you invite someone to access your desktop. The viewers and desktops can be any combination of Linux, Windows or Mac.

Unlike skype, viewers can interact with the desktop.