Quoted from PinballHelp:

PinWiki has a number of issues:
1. It's a Wiki... it has no real "verification" or editing process - anyone can edit a page and change some information that could cause a person's machine to be worse off than before. There are no checks-and-balances.
2. PinWiki is not any more stable or secure than Clay's guides. The site has no clear policy regarding copyright - there is nothing saying the content is put into the public domain - it's clearly owned by somebody (or a bunch of people)
3. When you click on the "about us" at Pinwiki here's what you see:
"PinWiki was created for the purpose of holding all things pinball in one location. There is a lot of information available on the Internet for pinball but its scattered everywhere. The goal is to incorporate the many groups of information into one centralized location that can be contributed to by all.
PinWiki was launched on April 21, 2011 at 9pm officially, kicking off with a wiki and a forum. All information contained in this wiki was added from that date on. "
The owner(s) of Pinwiki as far as I know are secret, and insist on keeping under the radar, and there's no guarantee the site could go pay or disappear from the Internet at any time.
Some areas of PinWiki are pretty cool - and I can see some potential, but there is no clear overseer taking responsibility for the legitimacy of the content, and the content is not public domain, so the site is as much a ticking time bomb as Clay's guides. There have been discussions about this over and over.. if the site is really intended on being a true public resource, it should require all content submitted to have clear public domain or CC licensing terms like standard Wikipedia.

Quoted from PinballHelp:

Why don't you all post an IP policy?
Why are you so cryptic over who owns the site and who owns the content?
As long as you're going to promote PinWiki, others are going to want to know why they should contribute and what happens to their contributions?
This is a basic policy that every other Wiki on the planet has. Why won't you address it?
This is a very important question. It's not worth "letting go." It has to do with whether or not anyone's contribution on that site ends up being owned by someone else, who the owners are, and what their intentions are. It makes no sense to not outline the site's terms regarding intellectual property. This could be addressed instantly, yet for years, you refuse. Why is that?
Look, if you simply say, "I put a lot of content in that system. I own the domain, and I reserve the right to that content, and I can do with it what I want to do." then I respect that. But at least say that. I will say that over my site, pinballhelp.com - I own that content, it's mine. I'm going to do what I want to do with it. If PinWiki is your site, why not just say so? Why is it secret?

Quoted from LTG:

AFM. Martians taste like BACON. Just in case.
LTG : )™