The Firefox extension is a ghost...it's invisible...unless you first go to the Zoho Notebook page and sign in. Then, suddenly, you have right-click options - which disappear if you sign out! Also, people have been losing their data!
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.