On the Mindoop blog, there's a new post talking about some of the issues that the Zend Framework could cause with the SEO for your site - a simple reason, really.

Zend framework is becoming a first choice framework for a large percentage of PHP developers. It's native support for advanced URL routing makes implementing search engine optimized URLs a breeze. Or not?

Because of the reserved words for the controllers and the multiple ways to access the actions below it (his example is case_studies, case-studies and case)studies) make three different ways to get to the same content - a SEO no-no.