The Google Analytics stuff is just creepy, and getting darned near as ubiquitous as doubleclick.net tracking cookies.
I've got mixed feelings on this. As somebody who does a bit of web development, it is nice to see how many visitors you're getting, what browsers they're using so you know what to design for, etc.
But, is this speed due to compromise the security?
Not necessarily. Right now, Chrome is the only browser that compiles JavaScript, although I think Firefox has plans to compile JavaScript in the next major version.
Keep in mind, JavaScript is not Java. Java already uses a JIT compiler, but JavaScript never has.