Dopplr is a microblogging site much like Twitter or Jaiku. Unlike those two sites, Dopplr focuses on frequent travelers and the travel community. Originally in a closed, invite-only beta state, Dopplr is now open to the public. Anyone can sign up for a free account and start sharing their travel information and stories with friends.

Since Dopplr focuses on travel, it is ideal for people who travel a lot or have many friends throughout the country or throughout the world. Frequent travelers can inform their friends of their trips, where they are going, how long they will be gone, and even the mode of transportation they will be using. People with distant friends can inform those friends of upcoming trips to their region, making reunions and meetings easy to coordinate.