While I agree with the topic of this thread, it is worth pointing out that for a lot of people in Africa, English may well be a second language. Having said that, it is well accepted that learning and becoming profficient in English is probably one of the biggest challenges a person can face, so let's cut the other less fortunate guys a bit of slack.
My pet peeve is on a sub-heading of this thread, which is people writing like they speak, ie- slang/patois whatever you want to call it, and doing so because they are simply too idle to apply themselves eneough to show a little respect to others whose English may not be great to start with. These poor souls suddenly find themselves drowning in what appears to be (and often is) gibberish thanks to an insensetive person trying to be amusing.