Keep in mind its just the CBD, which will already have good...

Keep in mind its just the CBD, which will already have good access for cables etc, its not residential, so this is in effect TPG having a no-installation cost to put business in Adelaide CBD on-net.

It is pretty significant and a good thing for TPG, installation costs can take upto 18months to recover AFAIK, so it gives TPG a big boost. But its unlikely to have much effect on NBNCo's plans for Adelaide or elsewhere, they are still going to offer their business services (which they are just starting) so in the long term it will come down to monthly charges.

NBNCo's business service will open up competition for buildings TPG/VOC/TLS have on-net, perhaps NBNCo wont have as high end services though (as in this Adelaide example) so high end customers are probably safe. I think there will be good benefits to telcos from NBNCo connecting smaller business which probably couldnt be justified previously.

I think its highly unlikely small towns are going to try competing with NBN.