>if someone used the… dictionary to create abbreviations

what CK is saying, I'm guessing, is that if you use such a dictionary to add 'clever' initialisms to your posts and your reader(s) then have to use the same dictionary to understand your posts, then you're not saving much time by abbreviating but only indulging in mental masturbation. OTOH, if certain initialisms just seem to fall out of the normal flow of posting, then maybe that's a good-thing.