This was discussed a few years ago and I do not recall the end result.
My opinion, create a list of parameters. That goes across the top. Along the left side are dive shops that wish to be included or that people add.
Caveat that it is using best available info and contact the dive shop for verification.
Here is my start for a list of attributes:
1) Shaded boats
2) Beach surface interval (BC = beach club. R = remote)
3) Boat size (6 = six divers plus DM, 20 = twenty passengers, etc)
4) Nitrox available (may be pointless if it is universal)
5) Training available (possible codes for different levels)
6) Pick up points. (C = Caleta and south. DT = downtown and south. N = northern hotel and south)
7) Cruise ship passenger option
8) Combined snorkel/scuba trip
9) Tank Size (80 100 HP120, etc)
10) SI food/drink (water/fruit - water/pastries - hot meal)
11) Range (west side, west and east, west no north)
12) Boat Amenities (none, jackets, head, etc.)
13) Cert agencies (PADI, NAUI, SSI, etc)
14) Departure times (8am downtown, 9am downtown, 8:30am caleta, etc.)
15) Trip Offerings (2 tank mornings, 3 tanks, 4 tanks, etc)
16) Equipment handling (yes, no, yes no wetsuits, bc and fins only, etc)
17) Number of divers required to send out a boat (morning always offered, 3 for afternoon, 4 for night dive, etc)
18) Payment options (cash, credit card, deposit required, etc)
19) Referral Dives (4 shore, 2 shore 2 boat, 4 boat)
20) Contact info
21) Arrange cenote trips (yes/no - may be universal so pointless)
22) Boat Charter available (yes/no)
23) Notes (scheduled reefs, upcharge for north and far south reefs, etc.)
Just brainstorming.