Hüssy oversees Zeustracker, a Web site listing Internet servers that uses Zeus, a kit sold for about $700 on shadowy cyber criminal forums to harvest data from computers infected with a password stealing Trojan horse program.

... and the even more relevant:

In early April, Hüssy began tracking a Zeus control server used to receive data stolen from a botnet of more than 100,000 infected systems, mostly located in Poland and Spain. While investigating this newfound Zeus control server, he noticed something unusual: the "kill operating system" had just been issued to all 100,000 infected systems.

So if I were to make a snarky list as well, I might say:

• The article doesn't mention what OS Hüssy actually runs
• The machines weren't his, he was monitoring a botnet control server to which they communicated
• The only reason Hüssy was aware of them was because they were infected
• He noted the "kos" command issued and wanted to bring awareness to it

Cheers.