How exactly do you think this wiki would be different from OWASP?
Please not that I do not wish to nullify your suggestion. I like it. In fact, I had a few similar thoughts, like placing accessible links to all the exploits and tools in Web App Sec world (like Portscanning using Javascript/CSS, Hackverter, Browserfry, etc. etc. etc.) under one roof.
What I wish to say that instead of staring a new wiki from scratch, why not use OWASP (may be start a new project)?
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I'd love to change the world,
but they won't gimme the source code.
Code in my Bug!