The news this past week that some 600,000 Apple Mac computers had been infected with malware and hijacked into botnets signaled an "end of the innocence" for Mac owners who have long been told -- and believed -- their computers were safe from the hacks and attacks so common to Windows PCs.

Macs were different, the mantra went, and the Mac operating system safe from the kinds of security holes always popping up in Windows.

In truth, any Mac can be hacked, so why the belief they were somehow "safe?"

It's all down to numbers -- as in market share.

Macs, though powerful, useful and even predominant in certain fields like publishing and graphic design, have until now been considered "niche" computers, beloved by their owners but spurned by the majority of the computer-buying public in favor of the ubiquitous Windows-running PC clones.

(Full disclosure: This is being written on a Mac, and I've been a Mac user for 15 years.)

So until now it hasn't been worth the time of the spammers, scammers and malware-writing computer criminals to go after Macs, when the countless millions upon million of Windows computers were such an attractive target.

That has changed, as Apple's share of the PC market reached 11.6 percent in the fourth quarter of 2011, a growth of 20.7 percent compared to 2010.

In fact, Apple was the only computer maker to see growth in the year, as all the Windows PC vendors saw their market shares drop.

Those kinds of numbers bring Macs to the attention of those with criminal intent, experts said.

"It became clear to the cyber-crime world that there's money to be made with OS X malware, and we've seen an increase in OS X malware since then," Roel Schouwenberg, senior researcher for security company Kaspersky Lab, told PC Magazine.

"I hope we can now finally lay the 'Mac has no malware' myth to rest."

The tipping point was undoubtedly the Flashback Trojan, which once infecting a Mac computer could give criminals control of the machine, allowing them to use it as part of a spam botnet.

The malware first masqueraded as a Flash Player update, but if downloaded by the user it deactivated some of the computer's security software.

A subsequent version of the malware could infect a computer even if the user did not download it or interact with it in any way.

Some Web sites, if visited by the user, could download the Flashback Trojan onto the Mac without warning.

As third party security companies jumped in with software solutions, Apple promised a tool to detect and remove the malicious software, making it available to Mac users Thursday.

It also said it was working with Internet service providers across the world to shut down the network of computer servers and botnets presumably hosted by the malware authors and currently supporting the Flashback Trojan.

Mac owners, always eager to extoll the virtues of the Apple product, must now acknowledge that in security issues at least, the Mac is now a victim of its own success and growing popularity.

Congratulations, Mac owners, on your favorite computer joining the big leagues.

Oh, and be careful what you wish for.