President Obama is the best-known politician to be exploring the possibilities of new technologies to converse with the people. Others must follow his lead and innovate. It is inevitable.
Rio will have to look after the legacy of infrastructure. But it's unclear who will run the sports centres after the Olympics.
Elected representatives are so embedded in the basic notion of what constitutes a democratic nation that it has become indistinguishable from any other form of democratic governance.
When Seoul hosted the Games in 1988, it became a symbol of the Asian Tigers' ascent onto the world stage. In 1992, the Barcelona Olympics represented the unification of Europe. And when Rio plays host in 2016, it will reinforce the growing importance of Brazil and Latin America as a whole.
I strongly believe being mayor is the public post in which you have the greatest opportunity to change peoples' lives for the better. People live in cities, not states or nations. As a mayor, you are connected directly to citizens.
Rio is an energetic, vibrant place, full of beauty and nature. But we face the kinds of problems any developing metropolis does - with pollution, traffic congestion, poverty. Distribution of green areas, for example, is not uniform. Madureira, the heart of the suburb in Rio, is a concrete jungle.
In Rio, 1.4 million of the 6.3 million people live in favelas, or slums. They are all over the city, but favelas are not always a problem - sometimes they can be a solution, if you have the right public policies.
In Rio we built a Center of Operations, a situation room that gathers information from municipal departments and allows us to manage and help decision-making. I can check the weather, the traffic and the location of city's waste collection trucks. Each of 4,000 buses in the city has a camera connected to the situation room.
