If the ads contain malware, you'll only get tracked if you install/allow them to. The browser is a sandbox, and only allows stuff it translates to the page for scripts to use. You apparently don't do much with tech besides comment on specs. I am a programmer. I know how viruses works, how they get on your computer, and that 99.9% are because of the end user being a trained click-through-warnings machine. In fact, the biggest virus out there is Norton. I don't see ANY virus tools on linux, because people who use linux are too smart for viruses and petty stuff like that.

For someone who supposedly knows alot about programming, etc. you mention the point about Linux. One of the main reasons there aren't many viruses on the Linux market is because it doesn't hold a majority market share like Windows does. Why break into a bank with only $1000 in the safe when you can break in to a safe wit $10 million? Same concept applies to why hackers target Windows over any other system. The same is now happening to OS X now that it's gaining some popularity. While your reason may stand true, it's not the only reason.

Also modern day backdoors (different from viruses) don't need explicit user permission to infect a system. The fact that they can be written into an executable JS script and then hidden within say a Wordpress plugin, could spell disaster for the unsuspecting end users.

"If the ads contain malware, you'll only get tracked if you install/allow them to"
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Yeaaaaah, no. General knowledge of modern virus history absolutely says otherwise.

"The same is now happening to OS X now that it's gaining some popularity"
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I don't buy that. Apple is big enough that hackers would be foolish not to consider it. Especially as Apple computers are big among professionals. OS X still only has a handful or two of viruses in its entire history and a LOT of them are not recent.