We are a network security company helping big Internet Service Providers to manage the security/abuse issues of their subscribers.
Let's say a computer at home is compromised and remote-controlled to do stupid things like spamming or attacking other networks, we have a sensor network to identify this issue and then run through a defined proccess to mitigate and remediate the problem.
We are also using all the data we collect to build reputation lists about internet resources like IP addresses, domains, and others.