For example:
A small pack of wolves have surrounded and are threatening to devour a weak person, whom the PCs want to protect. Directly attacking the wolves would not ensure the weak person's safety because they are close enough to strike before anyone could get there. Diplomacy would obviously not have any effect, since the wolves would not understand any language. Intimidation, however, is not necessarily a language based means of communication and would work to drive the wolves back a bit. Other characters might use the Nature or Stealth skills to help succeed in rescuing the weak person. Intimidate, though has the advantage of being used in quite a few social encounters as well as the possibility of being on one's class list to pick up for free. The other advantage of the Intimidate skill is that it is a fun skill for some people to roleplay.