Dont believe everyting you read. Did they explain in detail how they established the estimate of half a million? or did they pull the number out of some oriface.
The malware is installed on some Macs and each mac owner should be aware of these malwares, how to avoid them, how to detect them, and how to remove them.
From a terminal app, run these commands. They do not do anything they just read the values.
defaults read /Applications/Safari.app/Contents/Info LSEnvironment
defaults read /Applications/Firefox.app/Contents/Info LSEnvironment
defaults read ~/.MacOSX/environment DYLD_INSERT_LIBRARIES
they should return "does not exist",
bob[18:52]~>defaults read /Applications/Safari.app/Contents/Info LSEnvironment
2012-04-06 08:07:43.011 defaults[5202:707]
The domain/default pair of (/Applications/Safari.app/Contents/Info, LSEnvironment) does not exist
bob[08:07]~>defaults read /Applications/Firefox.app/Contents/Info LSEnvironment
2012-04-06 08:07:43.072 defaults[5203:707]
The domain/default pair of (/Applications/Firefox.app/Contents/Info, LSEnvironment) does not exist
bob[08:07]~>defaults read ~/.MacOSX/environment DYLD_INSERT_LIBRARIES
2012-04-06 08:07:52.905 defaults[5204:707]
The domain/default pair of (/Users/bob/.MacOSX/environment, DYLD_INSERT_LIBRARIES) does not exist
If they return anything else go here how to remove Flashback