Right now, as the mod sits,
http://wotlk.wowhead.com/?item=16243 will not work (it shouldn't break the site though). Instead it -should- default to
http://www.wowhead.com/?item=16243 (notice the sub-domain prefix change).
If you posted an item that doesnt exist in live, you should get an item not found message instead.
So, nothing really should "break". I do however, have a temporary hack fix (hax!) in mind, but i won't be able to write and test it until tomorrow morning (working 12hrs/day sucks!). I need to sleep sometime
Also, "the site breaks", tells me nothing about your problem. A link to the actual post, a php error message or something would give me an idea of whats going on.