Hi Philippe
I was also confused of whether I should use zope 2 or zope 3.
The zope book, which you found, is targetting Zope 2.6 or 2.7 - the whole documentation Area on zope.org is basically outdated and a total mess. Sorry for that, but actually zope.org is not in a good shape which will hopefully change in the future.
are for zope 3 or zope 2. Or is zope 3 backward compatible with zope 2 ?
No, but many good things from Zope3 get backported to Zope2 using a bridge product called "Five".
Is there any doc about zope 3 ? Since the book is made for zope 2, I think I'll stay with that one. I can not go without documentation.
There is an excellent book on Zope3 by Philipp v. Weitershausen, there will be an updated version out at the end of the year, see http://www.worldcookery.com/ for further infos, and also some quick start tutorial stuff about Zope3. Basically, if you want to develop your website from scratch, then you should go for Zope3. It is a complete rewrite with many new and good concepts. There is also a different mailing list for zope3 users.
different products available and my god ! there are hundreds of them.
If you want, you can have a few full blown CMS Systems, based on Zope2: look for Plone, Silva or even ZMS. Or you can use the CMF (Content Management Framework) to build your own Site. Would you rather use a full blown solution, including wysiwyg Editing, Workflows, and many predefined content types, so you can quickly begin customizing its visual appearance or do you want to build your own? Kind Regards Maik