Implement a cache for the meta tags

As the code is now, nodewords.module retrieve the meta tags associated with a node each by each. Using a cache to contain those meta tags would save some database queries.
As the module implements hook_nodeapi(), it would not be difficult to clear the cache from the rows that needs to be updated, or removed.

The same is true for the meta tags associated with other Drupal objects (user profiles, taxonomy terms, vocabularies).