Hellerstein seeks to gather this information by simultaneously querying millions of computers over the Internet.
In web search, the system has to provide search over billions of documents stored on millions of computers.
Conficker (aka Downup, Downadup and Kido) has infected millions of computers, installing code that gets them ready for further commands.
The last big worm like this, Conficker, infected millions of computers in almost 200 countries in 2008.
Tens of millions of computers are infected with botnets that can fake ad clicks, and these infections have proven remarkably difficult to eradicate.
That means most of the tens of millions of computers in America that have been retired from their primary functions have no obvious monetary value.
But many experts say the $149 Windows is competitive because it is relatively inexpensive and works on millions of computers that are already in use.
The internet is made up of millions of computers all connected together in a network.
Tens of millions of computers were reported to have been hacked that year.
A "deadly serious" bug potentially affecting hundreds of millions of computers, servers and devices has been discovered.
Here in California they're at the cutting edge of cyber security, using this virtual reality map of millions of computers to hunt hackers.
