Protests Powered by Cellphone

AS thousands of protesters marched through Manhattan during the Republican National Convention last week, some were equipped with a wireless tactical communications device connected to a distributed information service that provided detailed and nearly instantaneous updates about route changes, street closures and police actions.

The communications device was a common cellphone. The information service, a collection of open-source, Web-based programming scripts running on a Linux server in someone's closet, is called TXTMob.

TXTMob works like an Internet mailing list for cellphones and is the brainchild of a young man who goes by the pseudonym John Henry. He is a member of the Institute for Applied Autonomy, a group of artists, programmers and others who say their mission is to develop technologies that serve the social and human need for self-determination. (The group was behind iSee, a Web site that has maps of surveillance cameras in Lower Manhattan and calculates routes for those seeking to avoid them.)

He conceals his identity as part of an agreement with other members of the group and out of concern that he might become the target of an effort to force disclosure of TXTMob members' phone numbers, which are kept in a database he maintains.

TXTMob allows people to quickly and easily send text messages from one cellphone to a group of other cellphones. This in itself is nothing new: other mobile networking systems like dodgeball.com and bedno.com already exist.

To sign up for TXTMob, users enter their cellphone numbers into the TXTMob Web site, www.txtmob.com. To thwart spammers, the system uses opt-in registration: a machine-generated authorization code is sent to each registered number and must be re-entered into the Web site to activate the registration. TXTMob is designed to carefully maintain members' privacy, not surprising given why most are using TXTMob.