Part of being professional is appearing professional in all you do, in this case communication. You get lazy on a forum, you'll start to get lazy elsewhere. Should his resume carry the same grammatical and spelling errors as his post, CCIE or no CCIE, employment will probably not be forthcoming. After all, if he doesn't care enough to use the correct words in his writing, how sloppy will his network setup be?

And yes, it does carry over; I've seen in more often than not.