So. I noticed that in wp-blog-header.php:
@header("Expires: Mon, 26 Jul 1997 05:00:00 GMT"); // Date in the past
@header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); // always modified
@header("Cache-Control: no-store, no-cache, must-revalidate"); // HTTP/1.1
Don't the above headers defeat the point of the nifty caching that HTTP allows?
Why not set the Last-Modified header at least to be the actual date that the content was last updated? No point in making the user download a webpage again if it hasn't been updated.