Post installation

I used to work with tree-based cms, but now I need Drupal because of its fantastic module archive. However, Drupal's jargon is like chineese for me. I read the documentation, some tutorials and several forum threads, but after one week of full-time studies of Drupal, I still can't understand -- and found no clear definitions -- for: vocabulary, catergory, term, topic, article and node (it seems that there are synonyms). In a tree-based CMS, there is no such questions. I'm seeking for explainations of drupal's jargon using practical examples.

Has anyone done anything with a module or a block for displaying snippets from IRC sessions? I'm thinking of doing this, but wanting to know if the wheel has already been invented before going to the quarry.

It seems that the Drupal (e-)book ' Building Online Communities with Drupal, phpBB, and WordPress' describes Drupal 4.7.0, although that version has yet to be released. It makes it rather confusing for people like me who are (still) using an older version.

Is it possible to remove the mce_real_ part from TinyMCE script.

EXAMPLE: mce_real_src="EXAMPLE"

That appears as well as the normal html src="EXAMPLE"

Wastes hosting space, can it be removed?

A client asked me for dual colors menu items and a dual color title. The title must have a part with an italic style, something like mysite.com
For the title i noticed that if I wrote it with the tags it works, but in the title of the page (in the browser) I can see the tags.
There is a way to do colors and styles in menu and title, better with some css?
Thanks and an happy new year!!!

How do I allow users to post under certain categories only?