Dancing David
Penultimate Amazing
Yes, early intervention seems to be quite helpful - as much as in training the parents as the child!
Erk... my 19 month old son is somewhat delayed, but none of the people we've seen seem worried about it. I think I just know too much and worry about it. He certainly doesn't show a lot of the "typical" early signs of autism, but I still wonder sometimes.
The loss of language acquisition is the main one, and attention/over focus to non-social events.