Pandemic preparedness
One very real threat to the survival of our species is an outbreak of a disease that is as deadly as HIV and as contagious as the common cold. Such an outbreak could happen at any time, whether caused by transmission from animals, a mutation of an existing virus like influenza, or a maliciously engineered virus.
We must be ready to respond rapidly with a two-pronged defense: epidemiological and medical. Emerging decentralized technologies can aid both of these to create a very effective planetary immune system.
We dealt with such a threat in 2003: SARS. SARS 
was very easily communicable and fatal in 9.6% of cases [1]. It was contained so successfully that only 8096 people were infected before it was eliminated from the human population. The containment was not high-tech; the main strategy was to detect and isolate all suspected cases of the disease, walling in the virus before it could spread.
Smallpox was hunted off the face of the Earth by a heroic, concerted effort of 150,000 UN doctors tracking and isolating every case of smallpox. This was done in 1977 without digital communication or data-gathering technologies. With modern communications, we can do this much more quickly by gathering information from the victims themselves and their families and neighbours, without needing to send in teams to survey areas. Open source, open content platforms — specifically Ushahidi — will allow anyone to report a case of a pandemic and will map out the occurrences. In the event of a pandemic, this will allow us to know exactly where a virus is, rapidly alerting us to new outbreaks, and enabling us to quarantine those areas to contain the virus. This simple, user-generated way of tracking information may well save the human race. Odd though it may seem, one of the key factors that will determine our species' survival in the event of such a pandemic is how much we have spread Internet access to different people in different parts of the globe.
On the medical side, better, smaller, faster, cheaper scanning and genome-sequencing technologies are emerging that allow us to quickly identify diseases. We can now sequence the genome of a killer virus within days or even hours. (SARS was sequenced in 31 days, and the technology has progressed dramatically since then.) This information can be spread around the globe instantly and be used to diagnose the disease. With microfluidics , the diagnostic tools themselves can now be miniaturized to the size of a postage stamp (the 'lab-on-a-chip' concept). In the event of a pandemic, this with allow sophisticated rapid diagnosis to happen at any place, allowing for accurate tracking of the disease.
Rapid diagnosis and response will contain the infection, buying time to work on a cure. Sharing the genomic information of the virus globally and openly will allow many scientists to immediately start looking for a cure. A pandemic will be a uniquely motivating problem for open source scientific research. Cloud-computing approaches to rational drug design, like the DrugDiscovery@Home project, may turn out to be invaluable during such an pandemic. Millions of computers, connected by the Internet, could work on assessing potential cures for the disease.
