Sanjit Biswas, 25
Cheap, easy Internet access
In most mesh networks, all the nodes that receive a particular data packet forward it on; but in Biswas's version, the nodes "talk" to each other and decide, on the basis of the packet's destination and their own signal strengths, which one of them should forward it. The protocol also takes into account changing network conditions, as users sign on or off, or, say, a passing truck blocks a node's radio signal. Biswas's protocol, combined with commonly available hardware components, allows Meraki to produce Wi-Fi routers that cost as little as $50. (The routers Biswas used at MIT initially cost $1,500.)
Here's how a Meraki network works: a user plugs a router into a broadband Internet connection; that person's neighbors stick routers to their windows, and a mesh network of up to hundreds of people forms automatically. Users can give away or sell Internet access to their neighbors. There are already Meraki-based networks in 25 countries, from Slovakia to Venezuela, serving more than 15,000 users.