TWITTER is a free social networking and microblogging service that enables its users to send and read each other updates, knows as tweets. Tweets are text based post of up to 140 characters, displayed on the author's profile page and delivered to other users - knows as followers - who have subscribed to them.
FACEBOOK is a free access social net working website. Users can join networks organised by city, workplace, school, and region to connect and interact with other people.
People can also add friends and send them messages, and updates their personal profiles to notify friends about themselves.