5This is a study to obtain the psychological types of the main entrepreneurs of social networks sites and understand the psychological similarities between them. The personality theory of Carl Gustav Jung and the MBTI (Myers-Briggs Type Indicator) will be used as theoretical parameters. The development covers an overview of personality theories and a study of the Jungian personality theory and its relationship with the MBTI in defining introversion, extroversion, sensation, intuition, thinking, feeling, judging e perception. The objects of study are interviews and seminars from the entrepreneurs that founded the social networks sites with the highest number of hits in 2011: Mark Zuckerberg, from facebook.com; Jack Dorsey, from twitter.com; and Reid Hoffman, from linkedin.com.