Isaac's piece, Code quality: a concern for businesses, bottom lines, and empathetic programmers, ran recently on the Stack Overflow blog.
A simple metric for code quality code be how easy is it to delete any given piece of code.
There's no algorithmic way to judge quality code, but experienced engineers know it when they see it.
Jeff Atwood's Performance is a Feature blog post gets a lot of mileage with our writers. But code quality isn't on the same axis; it's not a feature you can prioritize. It's part of the development process.