What a great idea! I especially like the wiki aspect. There does seem like a gap in the market for a collaborative site that can't be easily dismissed by Muslims as run by Muslim-haters or right wing Christians making stuff up etc. Being associated with ex-Muslims would help its image a lot I'd imagine. Also a section of articles refuting common weak accusations/arguments levelled at Islam or Muslims (taqiyya etc) could help show what you stand for and distinguish you. Maybe CEMB would pay for the hosting!
Often on forums like this or on blogs someone posts a new argument or new piece of evidence or source for debunking some Islamic claim or whatever, but it soon disappears down the board or blog rarely to be read by anyone again. It would be great if there was a place were people could submit such gold nuggets to a collation of continually refined, permanent articles without hesitating that they were contributing to an ethically dubious site or having to write a whole new blog post or page about it. I imagine it would also increase the incentive for people to do research and discover such things. Also wikiislam doesn't have anything on a lot Islamic scientific/historical miracle claims for one thing.
A couple of suggestions:
You could have links in the articles or just on the site to the best blog posts/webpages/vids on certain topics.
It's an interesting and important question is how to organise the info. The structure would ideally be suited to the scenarios in which someone would use your site, such as they want to refute an argument that comes up in an online discussion. One idea is to have articles or headings within them entitled with common Islamic arguments.
I've only looked at it briefly but I heard joomla is a really good, user friendly tool for creating and administering websites that comes free with a lot of popular webhosting services (they generally have a sort of dashboard with such tools). Maybe someone has experience with that or similar products. It has lots of extensions for creating wikis etc. Examples of joomla made sites: http://joomlamadewebsites.com
Last year I saw there is a webhost that lets you use a test account to try out their website creation and admin tools (joomla, wordpress etc.) for free. I'll post if I can find it again.
EDIT: It's www.bluehost.com
which lets you play around with a free demo account. Normally you'd click demo account on their home page, then sitebuilder tab at the top and click simple scripts to install joomla on your demo site, but the last part isn't working currently.
I recommend contacting the guy who runs the rationalislam blog
. He could repost your request for help and raise awareness. He's a fan of Rationalizer, Captaindisguise, so is probably familiar with you too.
Btw, IERA have a new wiki site http://www.wikiquran.com/
It's just a blank page at present. Long may it stay that way!