You can find detailed information here:
http://www.reef.org/data/surveyproject.htm
The bottom line is that REEF is a conservation group that uses volunteers (i.e. recreational divers) to collect information on the health of coral reef species. As you dive more and more, you may find, like many of us here, that you get more interested in learning about what you are seeing. The "Gosh, there are a lot of fish down here." response shifts to a mode similar to young boys collecting baseball cards, swapping tales about who saw what, arguing the finer points of species identification, etc. It's all in good fun, and we have a great time trying to find unusual species or trying to figure out what life stage different fish are in. (It's surprisingly difficult!)
Many of us have the Reef Fish Identification book/CD, which is an invaluable tool for making sense of the whole thing. I heartily recommend getting a copy after you're certified. It makes the experience much richer.
But back to the REEF surveys. I can only speak for myself, but I find that, as I spend more time in the water, I become more aware of the fragility of the ecosystem there. You don't have to look far before you see evidence of pollution and reef destruction, from tires and beer bottles to damage caused by boat groundings. It makes you pretty humble, and makes me want to do something, even something as minor as reporting the species that I encounter, to try and help contribute to the goal of protecting the reef environment.
There are two organizations, Reef and Ocean Watch foundation, that offer fish identification resources to divers. They're both going to be at Ocean Fest. You might want to take a moment or two and check them out. They can explain their role much better than I can...
Many safe ascents,
Grier
