To paraphrase Diver0001, people on SB tend to know stuff. Most people, like me at the time, I would think don't know what a PADI is (well, maybe more now with everyone owning a computer). But still, I would guess a majority just go to the closest LDS and sign up for a course. Figuring Scuba is Scuba, don't they all just teach you how to do it? It's probably the PADI pushing shop courses idea more, but people just not knowing anything may be a certain part of the reasoning for no Instructor listings. Also, a list could be just one of names--anything more, like experience, no. of certs. the instructor has done, etc. wouldn't necessarily mean he/she is better than the next one. But it's probably the LDS thing...