In this sense it is different from broadcast television - such as that which you use to watch television shows on at home, as the signal has not been transmitted in order for anyone to receive it. However in some cases it can uses 'P2P', or 'Point to Point', broadcasting in order to send the video wirelessly. In other cases it can use multipoint or mesh wireless links, but in all these cases it is still not openly transmitted for anyone to receive.
The main use for CCTV is as surveillance where it is used to monitor areas of high importance or that contain items of significant value. For example it is used in places such as banks, military installations, airports, casinos and other high security venues. At the same time it can also be used in smaller scale locations such as convenience stores and restaurants, or in hotels. As well as being used to protect that specific area they may also be used in some cases to protect the customers, visitors or staff and do not just guard against theft or vandalism, but also against physical acts of violence or accidents.
CCTV can also have a range of other uses. For example it can sometimes be used for distance education, though this may also work by employing other tools such as video conferencing software and hardware. CCTV might also be used in industrial plants and scientific experiments in order to dangerous areas. This way individuals can observe for example a radioactive room remotely without having to be there and thereby risking their health.
An interesting and very advanced form of CCTV can provide recording over many years, or can be entirely automated using e-mail alerts, motion detection etc. They can also be used covertly for experimental reasons. In the home, cameras might be used in conjunction with an intercom and a digital lock. This then allows individuals to check who is ringing their doorbell without having to go outside, and to then automatically grant them access or stay silent as the situation requires.
CCTV can also be used for surveillance and to record the general public. This is done with the intention of reducing crime rates, by acting as a deterrent; and also in order to aid police investigations by providing video evidence. This is a fairly controversial topic however and is sometimes seen as a violation of civilians' privacy and rights. This is particularly true in countries such as the UK, which is known for having the highest number of CCTV cameras in the world for that purpose.
In short CCTV is used either to record, remotely view, or transmit information to a single specified target. The majority of those looking for CCTV cameras however will be looking for them in order to arrange them around their home and/or office with the aim of deterring criminal behaviour and also of aiding the police in investigations if something should still happen with the hope of catching the perpetrator and hopefully having any stolen goods returned to paid for as a result.