Zoho's got something new: Notebook. If you've used Microsoft's OneNote, you'll grok it pretty quickly. It's a content editing system that lets you create multiple sheets in one document; great for big, complex projects.
Storage of PDFs, files, images, links, and whole web pages. Automatic capture of citation information from web pages. Playlist-like library organization, including saved searches & tags. Integration with WordPress and MS Word. Interface in many languages.
Clickable article giving an overview of history, distinctions and definitions, potential uses, current manifestations, and permutations of this thing called (conveniently, but not accurately) 'Web 2.0.'