See I can see w/r/t meaning "with regards to" because they are each individual words; I can understand w/o shortening "without" because they are practically separate words; but how is a/b short for a/bout? I have never seen that before.
I mean, welcome! I think you'll find that the people up in QC Discussion never adjusted well to having to read only one comic a day, and the people in the other forums just don't read QC at all. (Just kidding, some of them just pretend they don't read it)