I'm Korean. If the person is old person(professor or teacher etc) that I know, that's rude in Korean culture.

Hi, im from Brazil. Well, guess it depends. If the one is your friend, ít´s ok, if no, better not point =)

in, indian too, i think its bad to point fingers at people of high status, like priests, teachers or people of the like!

in china,pointing your thumb means thinking highly of someone,pointing index means victory on stage or in a match.pointing little finger means think poor of somebody.

In Finland pointing finger towards somebody is not probably insulting, but it's not polite. Parents teach children not to point other people, but sometimes people just forget to avoid using this gesture. I might just easily point my friend with my finger but I would definitely not point elderly people or someone prestigious with my finger. In Finland this gesture is quite common in unformal situations when you don't know somebody's name ("You there"-kind of situations).