A webcam is a video camera that feeds its images in real time to a computer or computer network, often via USB, ethernet, Wi-Fi or built directly into the unit (common with laptops and netbooks.) Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. This common use as a video camera for the World Wide Web gave the webcam its name. Other popular uses include security surveillance and computer vision and there is also uses on sites like video broadcasting service and for recording social videos . Webcams are known for their low manufacturing cost and flexibility,[1] making them the lowest cost form of videotelephony. They have also become a source of security and privacy issues, as some built-in webcams can be remotely activated via spyware.

http://en.wikipedia.org/wiki/Webcam