In 2004 the new Zope had started make it back into the old Zope through the Five project. In 2005 I also had the opportunity to use the new Zope in its pure, unadulterated form in a new project.
The overall experience of coding in the promised land of the new Zope was mixed. On the one hand, if you wanted to write Python code it was clearly a much cleaner environment than the old Zope. The new Zope also was great at supporting all kinds of forms of extensibility in a clean way through its component and configuration systems.
On the other hand, I found myself having to edit too many files at once to get things done. You'd have the actual Python modules that contain the application code, a Python module that described the API of the various objects in your system (interfaces.py) and a XML file that described how these objects plugged into the system and with each other (configure.zcml).
I'm a lazy developer. I don't want to edit three files where I can edit only one.
Why was this problem not as big in the old Zope after we added the new Zope technologies to it? An important reason for this was the new Zope's security system, not shared by the old Zope.
The new Zope had a transparent proxy system that made sure you could only access an attribute on a Python object if you had permission for it, otherwise you'd get an AttributeError. And you'd give yourself permission by adding it to the configure.zcml (or the interfaces.py, where it could then be picked up from). If you forgot, you'd be staring at an AttributeError.
I found this pretty hard to use myself. All together the new Zope slowed down the feedback cycle for me, making it hard for me to stay in the flow when coding.
Let's make it clear: I also really appreciated the qualities of the new Zope. But I thought that these complexities made life harder for myself and also would hinder the adoption of the new Zope by other developers. It was different enough conceptually already, and its verbosity could be quite intimidating to many.
In 2005 the shape of web development was undergoing a significant change. While there had been web frameworks for years, they were becoming more popular, and the concept was finally coming into a more clear focus. This was in a large part due to the rise of Ruby on Rails. In the Python world Django and TurboGears were making a big splash.
Ruby on Rails attracted developers from Java who were really happy to find reduced complexity of configuration. And here we were with the new Zope adding more of it. How was the new Zope going to compete as a web framework?
I saw these problems, but many of the other developers of the new Zope did not share my concerns. Different developers have different strengths, and the developers of the new Zope were pretty smart ones. Many of them had no problem editing 3 files at once and adding lots of configuration XML to configure.zcml. They could keep all of this in their heads and remain productive. Or, as they argued, doing it this way gained you something too and they didn't want to lose that.
It was my problem. So how was I going to fix this? In 2006, I decided to go around the center, and start a new project to try to turn the new Zope into a modern web framework: Grok.