Rubbish, I have many CD's of theirs.

No, they mean as in MP3 format. I did look at trying to purchase a complete set of none physical music. It's hard to give them my money...

Oops, I was wrong. It looks like AC/DC went digital back in 2007 with an exclusive with Verizon.

http://www.reuters.com/article/2007/08/02/us-acdc-idUSN01367...

I'm sure everyone who shelled out $12/album with Verizon's DRM is still rocking out to Hells Bells.

I think it was a joke.

Not allowed and possible are not mutually exclusive events.