The ongoing need to communicate and coordinate is fundamental for the success of any HFN. The term conversation space was introduced for the medium in which all this takes place—from forming community responses to delivering actions. The conversation space is (1) a medium of communication among (2) a set of players (3) who have agreed on a set of interaction rules. These three aspects are summarized in Table 2.

Table 2. Components of conversation space.

One of our early conclusions was that the effectiveness of the HFN rests on the quality of the conversation space established at the outset. It is not a foregone conclusion that an effective HFN can be established even when the players are trained professionals, as the situations in New York City after 9/11 and in New Orleans after Hurricane Katrina illustrate. In New York, the mayor understood intuitively that success would depend on everyone, including especially the residents of the city, feeling included in the relief effort. He made sure information was shared, even if piecemeal. While there were some initial coordination difficulties, the network came together and was effective in relief and recovery. A different picture occurred in New Orleans. The various agencies had major difficulties in coordinating and the Federal Emergency Relief Agency (FEMA) did not deliver what people thought it had promised. At all levels there was a lot of finger-pointing and wrangling over who would do what and who would pay for what. When the president put a new man in charge at FEMA, there was no immediate improvement in effectiveness or criticism of the agency. Attempts to impose standard military-style command-and-control in Louisiana and Mississippi were ineffective. This is not intended as a criticism of New York, Louisiana, or Mississippi officials, but rather an illustration that effective coordination may not happen even when all the parties want it to happen.

Certainly a major difference between New York and New Orleans was the sheer scale of the event. New York lost infrastructure in a limited area of perhaps 100 square blocks. The primary agencies in the network ultimately reported to the mayor. Police and fire radios provided basic communications in the "ground zero" area. In contrast, New Orleans lost an entire city and was part of a large area (90,000 square miles) with severely damaged infrastructure. All communication systems were knocked out; and as they were gradually being restored, the limited-bandwidth channels were overwhelmed by sheer numbers of citizens trying to use them. Many more agencies had to cooperate on the response. Coping with all this effectively was completely outside most responders' experience.

New York City quickly built trust among the responders and citizens. New Orleans experienced considerable difficulty in building trust.

But this is one of the lessons: the more overwhelming the event, the more likely turf-asserting tendencies will occur and interfere with the effectiveness of the network.

The overarching lesson is: the effectiveness of an HFN depends as much on the participating people and organizations as it does on the communication system through which they interact.