Page Comparison

...

if (req.url ~ "node\?page=[0-9]+$") {
         set req.url = regsub(req.url, "node(\?page=[0-9]+$)", "\1");
         return (lookup);
     }

Masquerade

Problem

Masquerade will start a $_SESSION value on every pageload in hook_init, thus creating a session cookie and breaking caching.

Solutions

Patch/Fix for Module

http://drupal.org/node/908194

This is a really common-sense change to the code, so hopefully it will be accepted. It looks like the Drupal 7 version is re-written so it's only 6.x-1.x we need to worry about.