It all depends on the forum.
In WoW, you're in the middle of playing a video game, where your controller is your keyboard. That pretty much says 'I gotta type quickly' if you don't have vent. So you shorten a few words.
In fact, know your history. A lot of the LOL and U R and all that came from before the Internet mainstreamed, when it was used as a method of communication between programmers. You only had one line of text, so you couldn't afford to spell everything out correctly. Thusly, communication -had- to become short and abbreviated.
Then more people got on the interwebs, and started talking with those people, and the speak spread, and you have the situation you have now where a lot of the vernacular comes from a desire to expediantly communicate.
It's beneficial because not everyone can type at 60wpm or more, so if they ever wish to communicate a thought some time this year, they -have- to abbreviate.
People communicate that way because it evolved from limitations of the media, compounded with limitations of the individual. Not to mention, a language evolves, and attempting to stop that is somewhat hypocritical; So the language of the 80's is English-as-it-should-be, but you shouldn't use the stylings of Victorian English? So 80's English is the height of English communication and cannot be improved upon? Some misspellings of words like 'Thru' and 'Tho' have become part of the language simply because they're superior to previous words. The language doesn't care about archaic rules, it's only purpose is to communicate.
That said, writing out a paragraph like this in anything but concise english is inexcusable.
But nitpicking spelling errors or what not just because 'it bothers you' is also inexcusable, on informal forums such as this. Did the idea communicate? Yes? Then it did it's job, and you're detracting from that by being nitpicky.
Lastly, whoever is douching on the title: It's called 'irony.' And if you -know- that it is irony douching on it is not itself 'irony.'