Let’s face it. The Zend Framework, like most web frameworks, has set some lofty goals: high quality components, a complete system for developing web applications, and simplicity. You can read the entire list of goals on the Zend Framework roadmap page. While quality code and documentation are important for frameworks—or any open source application for that matter, a true measure of success is mass adoption. After all, what good is a framework if no one is using it? As the framework is still sub-1.0 and mainly for early adopters, there’s an easy way to determine whether the Zend Framework is right for your development efforts. So who is using the Zend Framework?
Recently Lars Strojny posted to the framework mailing list to announce his project, PhpWishList (View a demo!). This prompted Zend’s own Gavin Vess to create a wiki page to showcase Zend Framework projects and applications. Shortly afterward, others pointed us to other projects found by searching Sourceforge and Google Code.
Do you have a Zend Framework project to show off? Post it to the wiki!
View Zend Framework projects on the wiki page.

Comments
MVC, input filter and routing/controller (like RoR) were the most appealing part of the Zend Framework -- and with future versions... I'm sure I'll find more stuff to enjoy.
Below are the clients who are using the resulted listing engine with cms built from scratch using Zend Framework.
http://www.westvancouverrealestate.ca/
http://www.macrealtyedmonton.com/
http://www.drobinsonassociates.com/
http://www.paulisaacs.com/
These projects are quite large and are associated with financing and data center business.
I think they've got the right basic idea, but I don't think that they're headed in the right direction. I hope I'm wrong. It would be nice to have a good framework. I'm updating a bunch of code from php3/php4 idioms to php5 and nothing on PEAR works with E_STRICT. I suspect alot of stuff is going to need to be written from scratch.
I primarily used the MVC framework provided by ZFW, as well as Zend_Filter.
I started writing my own MVC framework to aide my applications, then I gave Zend Framework a go. I'm never going to develop without Zend Framework again. The MVC concept is excellent. So is the Framework..
I'd never cached anything in my applications until I used the ZF, it took me 5 minutes from deciding their was a problem, to implementing a working example of Zend::Cache in a small project I've been undertaking. Ajax? No sweat. A tutorial from devzone and 30 minutes later, ajax retrieving cached news articles from an sqlite database.
I have no qualifications, certifications or commercial experience. I hadn't touched PHP in close to 18 months until a week ago. In 3 days, the Zend Framework hasn't become my swiss army knife - I wouldn't be lost without it - it's my tent, I wouldn't like to be without it. I've not used one library that has enabled me to do so much, so easily.
That's who I am and that's why I use the Zend Framework.