Mercury in the fifth house makes the mind creative, playful and public. A person wants not only to know, but to show knowledge in an interesting way: perform, joke, write, tell stories, play with words, lead intellectual contests, discuss news and attract attention through wit.
In a strong expression this gives oratory, pedagogical, literary and creative talent. The person learns easily when the subject is interesting and can just as easily ignite interest in others. Journalism, blogging, teaching, children's clubs, intellectual games, excursions, contests and creative development of children suit this placement.

