I added my college proffessor as a friend on facebook?

i think the old high school teachers are a little weird, i would rather keep in touch with them via e-mail if we were close. But the professor, i can understand...if professors make themselves available on facebook, then they are willing to be contacted, and thats not too weird. Esp. a profesor that is more like a friend, as many of my art professors are..the fine art professors are not like others, its a different sort of relationship, i understand.