Jack Dorsey announced on Twitter last evening that he had founded two more companies, and would play the role of CEO in both those companies. He will split his time between the two companies that he is running right now (Twitter and Square) and the two new companies, one in the medical informatics space and one in the education space.

Without divulging many details, Jack mentioned that the medical informatics company was born out a discussion with his childhood friend who is now a Nurse, and the one in education space was similar to the work he did while he was an intern in New York.

When a SVChronicle reporter tweeted him to ask how many hours he plans to work in a week, Jack just responded saying he was busy discussing an idea with a friend that could potentially turn into a startup.