I'm actually continually amazed that even some technically inclined people misunderstand how memory works in /all/ modern OSes: recently I had a discussion on Twitter that went something like this: "OS X is horrible, it uses nearly all of my 8 gigs of RAM and my browser is horribly slow!" to which I replied, "it's perfectly normal for the OS to appropriate the RAM in the fashion you see in Activity Monitor; this doesn't mean your machine is slow due to lack of RAM." Unfortunately, even after a lengthy discussion and several forwarded links, I seem to have failed to make the case.

It would be interesting if someone more knowledgeable than I am were to do a write up explaining memory usage in OS X, Windows, and Linux; would be an awesome resource to share with curious tinkers who may be slightly misguided in their understandings of the inner-workers of their computers.