Unless you successfully signed up for Docker Beta you probably had trouble getting started with Docker Toolbox on Windows.
The typical issue is that the Docker Quickstart Terminal will refuse to start because Hyper-V is installed, cf. docker/toolbox #77. In fact this is related to Oracle VirtualBox 5.0 coming with the current Docker Tools release.
The usual advice is to just uninstall Hyper-V - which i consider a big deal, especially on Windows 10.