Tutorials: Drupal caching, speed and performance

To make it easier to find information on these matters, I've started the new handbook page Drupal caching, speed and performance in the Tutorials section of drupal.org. It's just a guide to information and tutorials on optimizing Drupal's performance, speed, and scalability, with an initial listing of fourteen resources. If anything is missing, you may edit it to add other useful Drupal performance resources.