But artists like Aphex Twin (SAW 85-92 for example) were popular before the internet became the massive file-sharing place it is today. I'd argue that whole genres of music were created out of the internet, rather than the internet popularising it.

Ambient/IDM artists like Helios, BT, Solar Fields are products of the Brian Eno 70's and 80's, which created AFX and then led onto the ambient/techno, but EITS and Mogwai are post-rock and are more influenced by the more instrumental indie like Hex and Slint. That's my theory anyway.