You run untrusted code whenever your browser loads a web page that uses javascript.  With more and more of the web requiring javascript to work, running untrusted code becomes less and less a real option if you want to get any work done.<p>Arguably, plain HTML is also untrusted code, and I certainly don&#x27;t trust every single one of the authors of my operating system and all of the os-level utilities and all the applications that I use, especially not Microsoft or Apple.  But I&#x27;m forced to use them for work.<p>A year or two ago there was some hoopla about Canonical collecting some information about Ubuntu&#x27;s users or something like that (don&#x27;t remember exactly) and a lot of people were up in arms about how they don&#x27;t trust Canonical.  Canonical&#x27;s reply was one of the most insightful I&#x27;ve ever read on the internet.  They said something like, &quot;um... but we&#x27;ve got root&quot;.<p>That&#x27;s a great point.  The makers of your OS, the builders of your apps, they have a lot of power over you that you grant them simply by using their stuff.  You&#x27;re effectively trusting them, even if you don&#x27;t trust them.<p>You could react by not using anything that anyone you don&#x27;t trust writes, or by thoroughly auditing all the source code of everything you use (you do use only open-source software which can be audited by you directly, right?).  But this is not really practical for 99% of everyone on the planet.