I think the latter is more common. I've never herd before of a dolphin seeking out human help (but then I come from a region where we have no sea).
What I found so remarkable about this particular case was that the dolphin made the connection between the fishing line and humans.
I very much agree with
RJD and
Deranged Nasat: the problem is how to define intelligence, particularly if it is of a different kind than ours? (my old Zoology Prof used to say: humans build bombs. No mouse ever would be such an idiot to build a mousetrap)
Trampledamage, I am no marine biologist so I might be wrong, but I was under the impression that dolphins are part of the whale family, just a different branch than the "classical" whales like e.g. humpbacks?
Anji, that's a very good point, imho. We should first get to know our own neighbourhood before we set out to explore other planets.
I am not quite up with the recent discoveries but from what I heard, certain elements of whale and dolphin language have been deciphered.
Has nobody ever thought of developing a sign language for communication with dolphins? It worked with Washoe, after all!
http://en.wikipedia.org/wiki/Washoe_(chimpanzee)