if your music is created digitally and then distributed exclusively digitally, then there's nothing to master. the format is the same. and as for compression/limiting, i hear that putting compression on the master bus is pretty popular these days
edit: to be clear, i mean digital distribution as in via the Internet. CD of course is technically mastering, given that the recording may have to be optimised to account for the flaws of CD audio
I strongly disagree with this. There's a lot more nuance to the process, and you can tell the difference between something that's mastered vs. something that's not, assuming you're not listening to a 128kbps mp3 that's been re-encoded twelve times over to the point it no longer sounds like the source anyway.
This is what izotope defines mastering as, and it's a rather important step in production that can take something that sounds like a demo to something that sounds finished. Just recording something with half a dozen tracks and releasing with the bare minimum (basic mixing steps such as levels, basic EQ, etc.) is often not enough.
Unless you're not referring to recorded instruments (which I was), I can't understand this argument at all.
