Relationships

There are already many different definitions of performance from performance art to theater and music for example. In what way(s) does VJing differ from or overlap these other practices? Is it sufficient to describe VJing as ‘technologically mediated performance’? In this sense isn’t an orchestral performance also technologically mediated? Has anyone tried to map these overlapping areas of practice? In ‘performance art’ on it’s own there are a huge range of approaches allied to different intentions, ambitions and presuppositions. Some of these hold as central the presence of the body of the performer. Where does VJing or, for example, telepresence relate to this?
Finally, is the ‘performance’ of an interactive installation a result of the interaction between the viewer and the software/hardware. In this sense can you say that an interactive installation is also an improvised performance?