Drupal Watchdog offers a fascinating look> at the
many performance and scalability features found in the recently
released Drupal 7. With the longest release cycle of any major
Drupal release to date, Drupal 7
contains more new features and architectural changes than any
"Over 50 contributed modules have been moved into core, several
subsystems have been re-factored, and many thousands of smaller
changes have been committed."