Good article - this covers the basic OO patterns in Go. I really like the simplicity of the design - objects are just structs and you can define a method for that object. Coming from C#, it's like every method is an extension method.

The only critique I have is that there's no way to verify that object X implements methods A, B, and C. When I'm using C# or Java, I often use an interface as a test to make sure I've done my work since the code won't compile if a class that extends an interface fails to implement all the methods.