> At first sight, the stuff at flossmanuals is basic - very, very basic.
> What's the point in creating a new portal? Why not just improve the existing portals by adding and updating information?
A lot of the documents at flossmanuals, like for openoffice.org, are placeholders to show what is possible, rather than being "the" documentation for a project. I agree there is no point in duplicating effort for projects like OOo that already have robust documentation sub-projects.
Readers don't need to know about flossmanuals.net, because it provides hooks so that you can feed a document to your own website. So you can use flossmanuals on the backend to edit your docs, and the updates automatically show up on your project website.
The point in creating a new portal is to create a platform that makes it easy to create documentation for a project that doesn't have any. In the open source world, there are a lot of technologies in use for documentation, which tend to be challenging for either writers (LaTeX, DocBook) or readers (ad-hoc wikis) or both. FLOSS Manuals provides a technical infrastructure that is easy for writers to contribute to (you don't even need to use HTML), and supports documentation structures (books with chapters) that are familiar to readers.