Cube maps are typically used to create reflections from an environment that is considered to be infinitely far away. But with a small amount of shader math, we can place objects inside a reflection environment of a specific size and location, providing higher quality, image-based lighting (IBL).[/quote]

and further in the document:

In addition to the standard coordinate spaces such as eye space and object space, we need to create lighting space— locations relative to the cube map itself.[/quote]

but I don't really understand what he means with "lighting space".

Can somebody explain me this? Or can point me to some other resources?

I've also seen Reflection with billboard imposters of graphicsrunner but that seems so much work to create imposters for all objects.

I was also thinking about Real Time Local Reflections (raytracing in view space in your depth buffer), but that is something I want to try next ( looks really easy to do so )