Seriously, most Brits understand written American English, and most Yanks understand written British English.  Slang of any kind is generally a bit more alienating.  Those who use slang can usually grasp standard English to some sufficient degree (though certainly not always), but it's usually more difficult for those who aren't familiar with a certain demographic's or region's slang or dialect to grasp what's being said in that manner.  So obviously some standard form of English would be preferable.  Standard languages are something everyone can learn and would benefit from learning, but slang...well...slang is slang.

The site itself is in English, so I would imagine that if someone wanted to discuss things in another language, they would start a site in that particular language.

I'm sorry MOP, but I don't think that it's simply a language barrier that prevents people from understanding you.  Your posts are generally short, cryptic, and broad, and yes, your slang or poor English certainly doesn't help this.