The obvious difference being that Tomnod is focused on actual imagery of the surface of the Earth, something that most people are already familiar with thanks to Google Maps et al., and even so AFAIK the project produced many false positives and no actual hits.

I have no idea what format the sonar data is in, but I highly suspect that it is not in the form of familiar imagery in which parts of a commercial airliner would be readily identified by untrained observers.