As evidence of both how futile the Zend certifcate is for some people, and yet how useful the Zend Examination system is for others - let me explain what happened to me.
I enrolled for the online self text programme being put out by PHPArchitect.
I have taken the fake test once. To my horror I failed at each of the 17 topics (or strands - to paraphrase Marcus above) except one, the five questions on "OOP in PHP5" - those I got all correct*.
Now on Marcus' OOP list I'd say I am at 5.5 (I yearn dreadfully to be at 9 or 10 - yeah, 'the code will speak to you' it sounds like nirvana).
But to be a fully rounded PHP programmer it is clear to me I am getting ahead of myself, I should know all the basics first.
In order to address my weaknesses I am doing two things:
-working through each chapter of Davey Shafiks "Zend Certification study guide"
-looking out for problems related to that chapter on PHP forums - as I said earlier
Working through Daveys book is the first time I have had my hand held and walked carefully through every basic point of PHP. I mean since I first picked it up in 1999 I just want PHP to work for me, I haven't had time to understand it! I was a html bodger in the days of netscape 3. Until a year ago the only learning I have done was when hacking and inspecting everyone else's classes posted on PHPClasses.org.
My point is this, I like Marcus' list - and it would be well cool to create similar just for Arrays, or just for a discipline like CVS.
For some people, your progress on each "strand" can be scored to a small degree - like a litmus test - and it doesn't require you to buy into the whole "Zend plaque on the wall" thing at all.
I only bother to post this POV, because it summarises my situation at this particular time and place with my particticular background - but I get the feeling I share this background with tens of thousands of others. We know we could be doing better, we are trying to improve, but just how good/bad am I?
* this included a question like 'which design pattern would you choose if you wanted a class which created other classes?' Factory, Observer, Singleton?
But to answer the question off the top of your head, you would need to be at about 6 on Marcus' OOP scale.