For whom and what is Zope 2/3?

What Steve Alexander wrote (quoted below) is some of the most enlightening text I've yet seen regarding Zope 3.  In accord with the title of this mail list, I would very much like to know more about these questions:

- For whom is Zope 3?  Who exactly is the target audience of this software?

- For what is Zope 3?  What will it enable that Zope 2 does not?  Does Zope 3 have a purpose or focus different from Zope 2?

As a complement, how do the answers differ when we switch all the '2's and '3's above?   I think some answers to these questions will get this list firmly on track.

Jon Whitener
Detroit Michigan USA

At 2/2/03 06:07 AM, in "Re: [Zope2-migration] New mailing list"
Steve Alexander wrote:
>No-one should choose Zope 3 over Zope 2 until the risk to them of doing so is outweighed by the benefits to them of doing so.
>
>A few examples of how I'd look at such decisions.
>
>* A small application made to familiarise oneself with Zope 3 that is
>  not for a client or on a particular deadline.
>  On Zope 3: No risk, some benefit in learning.
>  On Zope 2: impossible.
>  Use Zope 3.
>
>* A content management application of medium complexity, to be completed
>  for a client within 3 months.
>  On Zope 3: Very high risk. Perhaps some benefit in cleaner code.
>  On Zope 2: Known medium risk.
>  Use Zope 2.
>
>* An application that needs to take advantage of customisation of
>  individual instances on the same server, that is not suited to the
>  CMF, to be delivered in 6-9 months.
>  On Zope 3: Medium risk. Great benefit. This is the kind of stuff
>             zope 3 is designed for. It will be ready for this in time.
>  On Zope 2: Medium risk. You have to roll your own customisation
>             facilities, but do so inside the constraints of Zope 2's
>             less flexible framework.
>  Seriously consider using Zope 3.
>
>* A new novel capability for web applications, to be delivered in 6
>  months. For example, web services support, to support applications
>  not CMF style content management.
>  On Zope 3: High risk. Great benefit. The architecture is designed to
>             plug in different protocols.
>  On Zope 2: Very high risk. You might end up with something that
>             patches Zope 2 very heavily, but is not accepted into the
>             core distribution.
>  Or, if you don't need other parts of Zope, consider using Twisted.
>
>
>Imagine a wiki page with a list of a few kinds of application, and an estimate (that's updated every month or two) of when the risk of undertaking such an application with Zope 3 should be approximately the same as undertaking it with Zope 2.