I am pretty sure it's for people hosting their own sites and I think the author of the article made it sound scarier than it actually is.
From the Register
We're told the source code to ISC's crucial software packages are stored on a separate server, and cryptographically signed to prove they haven't been tampered with. Its BIND DNS server and DHCP tools are widely used on the internet, and included in most Linux and Unix-flavored operating systems.
"It was just the website – and it doesn't even look like we were targeted specifically," said Dan Mahoney of the ISC Security Officer team to The Register via email on Friday. "It looks like this was just one of those exploits that happens to CMSes of this nature."
You can forgive people for being slightly jumpy about an ISC.org compromise: its software glues the internet together, and the organization runs the world's F root servers [PDF] which are at the heart of the 'net's global address book of domain names.
People visiting the .org are likely to be involved in engineering software and hardware behind the scenes of the web; compromising them with malware could give attackers access to valuable systems and possibly the tools to subvert them.