[tbrownaw]

if you're writing simple webapps, which most people are nowadays, you don't really need to know what a linked list is. Your programming language of choice will abstract it away.

You still need to understand it at least well enough to know that you really shouldn't try to access random list elements. Just like you need to understand arrays well enough to not try to insert things into the middle of them.

[rikthevik]

I think Yegge was right about compilers. Without understanding low-level languages and how high-level languages get transformed, a programmer can never really understand the language he's working with.