From the jQuery site: "jQuery is a fast, concise, JavaScript Library that simplifies how you traverse HTML documents, handle events, perform animations, and add Ajax interactions to your web pages".

jQuery is also the base Javascript library in Drupal.

Also see the Weblink to PQuery.

Drupal has been good to me, no question about it.

I had planned to roll up my sleeves and do some PHP coding to make it work the way I wanted. But, between the Drupal core, Links and a few other modules, it pretty much does what I need already ( with maybe some more meta-data for the links ). So instead of coding PHP, I devote my time to creating content, which was the point of the exercise in the first place. It's worked very well for my purposes.

According to the Drupal web site,

Potential RDF use cases for Drupal - an excellent article about RDF in Drupal 6 - 7.

The Drupal RDF module uses the recently-rewritten ARC2 RDF Library if available but apparently does not require it.

From the drupal.org post, Semantic Search - Faceted Search and Semantic Web:

It's getting serious. Things are moving resolutely forward toward Drupal 6 and 7.

The seems to be some confusion about the difference between 'rule engines' and 'semantic web' applications.  See related link to "Semantic Web Inferencing versus Rule Engines"

Also a link to CCK-related modules.

From the project page:

Node linking and Metadata

The Relationship Manager module is intended to allow free-form links between nodes, recording not just that one page relates to another, but HOW it relates. ... The core module is made available to be extended by other modules that wish to make use of the generalized relationship management functions. Several examples of simple modules that leverage this power are provided as optional plugins.

The major plugins are: