Digital on-screen graphic

They are thus a form of permanent visual station identification, increasing brand recognition and asserting ownership of the video signal.

DOG watermarking helps to reduce off-the-air copyright infringement—for example, the distribution of a current series' episodes on DVD: the watermarked content is easily differentiated from "official" DVD releases, and can help identify not only the station from which the broadcast was captured, but usually the actual date of the broadcast as well.

On the other hand, watermarks pollute the picture, distract viewers' attention and may cover an important piece of information presented in the television program.

Some television networks may place additional logos or text alongside their DOG to advertise significant upcoming programs.

Another method commonly used by hobbyists and even low-budgeted TV stations in former times was Amiga computers with genlock interfaces.