Network Surveillance
Computer surveillance generally involves the monitoring of data passing over network connections.
Packet Sniffing is the technique used to monitor data traffic to or from a computer on the network. By intercepting communication between computers an investigator can monitor in real time or a future time the activities of an individual.

Malicious Software Detection
In addition to monitoring users information sent over a computer network, there is also a need to examine network traffic for malicious software, or bots. Malicious programs will commonly communicate to a central control server waiting for instructions or passing sensitive data to unauthorized parties.

Machine Surveillance
To monitor the activities of a person using the computer a surveillance program or hardware device is installed on the machine. These programs can monitor modifications to the contents of the hard drive, collect credentials, screen shots, emails, chats and surfing habits.

Social Network Surveillance
One common form of surveillance is to create social networking maps. Data collected from sites like Twitter, MySpace, Facebook, Buzz, or other social networking sites provide virtual road maps of activities locations. These maps can be data mined to extract information including personal interests affiliations and even GPS locations.