The main reason for BFT was to keep track of where all your troops were, and to avoid friendly fire situations when a lot of units were close to each other at night or in bad weather. BFT was first used in Afghanistan, where headquarters in the United States or the Persian Gulf could keep track of where all their Special Forces A Teams were.
Based on the Iraq experience, there is a lot of enthusiasm to distribute more BFT transmitters, and more tracking stations (perhaps using a PDA size display.) The instant messaging capability was very popular and company and battalion commanders all want it.
One of the more successful new communications devices used by American forces in Iraq was the Blue Forces Tracker (BFT). This is a locating device that uses satellite phone technology. For anyone with the software and access codes, you can display the location of everyone in an area who has an operating BFT transmitter. This was frequently done from a laptop in a vehicle. In stationary headquarters, the BFT display could be put on a larger computer screen. The BFT transmitters were distributed to infantry and tank companies, as well as some helicopters (like the leader of a group of gunships.) Another very useful function of BFT was the ability to send instant messages between users of BFT display systems. This was useful because radios often didn't work, but BFT usually did. Radios have always had problems because they are either FM (meaning line of sight transmission) or AM (subject to atmospheric interference.) Thus satellite based communications were much preferred. While headquarters could set up a satellite dish and establish a local Internet network, people in vehicles or running around on foot needed an Iridium satellite phone or BFT to be sure of always getting through.