I looked to get this done for a long time - I pushed and pushed for it then gave up - put a lot of money and time into getting the Library addon done but it was never developed fully - had a look at that wyswyg addon mentioned here but it has all kinds of limitations (can do simple edits on an existing page and I think that is what was intended) - finally ended up using Xenzine which is a superb addon.
Xenzine means I can make a page using the standard XF editor, in same time as making a post.
Has linked forum thread discussion if I want.
Has a categories system, is searchable on main search.
Has lovely abilities to display pictures, either default pic for category or per page on its category pages.
Can make an article page, or a category list act as homepage/ landing page.
Has EXCELLENT SEO presence on google.
Has excellent support and ongoing development.