• Flashback trojan reportedly controls half a million Macs and counting
• Half-million Mac infection estimate backed by new analysis
• Flashback Trojan infections estimated at 600,000 Macs

There seems to be a consensus of approximately 500,000 to 600,000 computers were affected by The Flashback Trojan. Forget about the possibility that some of the machines were running FreeBSD, Linux, Windows, or other operating systems. (Ars Technica)

After Apple released Java Update and Flashback malware removal tool there are two types of headlines:

• Flashback malware still on 140K Macs despite fix
• Flashback.K-infected Macs dropping rapidly, Symantec finds

Notice the language contrast between the two headlines. The prior sounds more negative then the latter.