A few fragments in reaction to Andreas' fragments:
 
"Media" or "medium" (I checked, this singular does exist in English) has
changed in its common usage, or put differently, the focus of this word
has been changed. Pyhtia sitting in Greece, inhaling fumes and emitting
words to be interpreted for a possible future is not associated
immediately with medium in our sub-set of media art. Media as tangible
material mediating between "sender" and "receiver" like paint, canvas,
paper, ink and possibly extending to sound and "ether" as intangible
media is another old use of the word. Media today mostly imply
electrons, which are pushed and pulled, and then produce something for
our human senses - seeing, hearing, feeling, moving in space and time or
being moved in space and time. Media Art as term is a case in point for
this change of what media as term has gone through. 
 
Any new term is used to convey (openly or 'secretely") a perspective,
like the one mentioned by Peter Weibel in Andreas thoughts. Such
perspectives are conglomerates of analysis and desires and help to
further thinking, conceiving and perceiving. They usually have little
immediate influence on the artistic production, but quite a strong
indirect influence since they become part of the artists' worlds and
since curatorial strategies do shape (insert any level of stronger terms
here) what is perceived and what is less so perceived as "media art". 
 
"Electronic Art" / "digital art" : Please allow me to again point to the
field of music. When electronically generated sound hit aesthetic
sensitivities after the Second World War, for just a few years in the
fifties "elektronische Musik" and "musique concrete" were juxtaposed
with specific aesthetic positions (both being "media art" in the sense
of using electrons to create sound). After "Gesang der Juenglinge" by
Stockhausen in the mid-fifties, this was not seen as valid any more by
the artists (composers). Only critics, musicologists and teachers loved
to hang on to it for another 30 or 40 years, since it was such a handy
and seemingly clear-cut distinction.

"Computer music" was preceded by "music with computers" and jelled to a
sort of floating standard in the sixties and seventies. It carried the
implication of music done with algorithms and computers on big
mainframes in institutions (academic in the US, radio stations and banks
in other countries). It was connected to "avant-garde" - which as some
may remember implied totally different aesthetics in East Europe, West
Europe, East Coast/USA or West Coast/USA.) 
 
The term "computer music" started to be questioned in the late seventies
/ early eighties. The implicit aesthetic agendas by those who used the
term were uncovered. The differences in the use between e.g. the West
and the East Coast in the US were surfacing. When I started to publish
the first CD-series with "computer music", it was clear that "computer
music" would not work - the way out was "digital music digital", since
it was the first large publication of digitally created music in a
digital format (which never the less meant that many pieces existed only
on analog tape and had to be re-digitized - and that the ears listening
to the music "still" needed and analog signal generated by loudspeakers
...)
 
With the advent of special chips for music (Yamaha DX-7, samplers)in the
early eighties and the acceleration of CPU's in the late 80s and more
drastically in 90s, "real time" in music became a commodity. And all of
the sudden we have "electronica" as a result of a few years of music
practice with computers outside the academic world (and inside another
world). This term does imply again certain aesthetics. What I find
incredibly interesting is, that with the advent of personal computing
power for digitally generated music, all of the sudden the old analog
musical instruments (ring modulators, modular synthezisers, LFO's etc
etc) came back in digital implementation (approximation). Much more
could be said to this.
 
"Media Art" does not include music as "just music", but as
trans/inter/multi-disciplinary ingredients. But I think it may be
worthwhile to look at the (longer) history of music with electrons and
interpolate to "media art" in comparison to non-media-art, i.e. art
without energy from nuclear power plants. 
 
I like very much what Andreas wrote: 
" As digital technologies are becoming more prevalent, art that
reflects on them needs to become less self-referential, less
autistic, and more culturally and aesthetically ambitious. It must
continue to articulate these experiential layers, it must confront,
dramatise and, at times, negate them." 
 
Looking at the development of music with digital technology one can
certainly draw a line in parallel to what Andreas postulates about art
with digital technology. The self-referentiality in approaches to
algorithmic compositions dominated the thinking, writing, and prgramming
in the field of music in conjunction with certain concepts of artificial
intelligence (the works resulting from this mostly did not lead to an
experience beyond the verbally acclaimed and their programmed
implementations - usually boring stuff ...). Culturally and aesthetic
ambitious productions in music had a hard time to grow out of the lure
of having found "it" (or "IT"). Maybe it will help to look at digital
technology in music and the arts as a tool of a totally different kind.
And a discussion on the paradigmatic change of "tool" from the analog
perspective of "forming matter" to the digital perspective of "defining
matter to be realized for eyes, ears, body, space and time" may be
helpful.
 
            Johannes