It can very much be an erotic tickling spot. It's one of those spots that when touched correctly can produce that incredible sensation that lies between a tickle and a light caress. What usually sets me off with my girlfriend is either the tongue in the crevice, or nails along the curvature of the outer ear. She's also incredibly ticklish along the ear as well. It's a regular component of tickling and the erotic for us.
For a great example, 40 Female Fingers from Real Tickling/TC (I don't know what clip number it is, I only have the vhs from their previous era) - one of the girls is tickled all over her ears with fingers and tongues.