A new way to check up on friends is taking the Internet by storm. Twitter.com makes it easy and free for people to group-message their social network about their whereabouts.
More than one million users worldwide have visited Twitter.com since its launch in 2006. On the Web site, users publish their current locations, actions and moods online, according to the New York Times.
Twitter users create and receive messages similar to Facebook status updates. Individuals can make Twitter profiles and add followers.