Digital watermarking is the process of embedding information into a noise-tolerant digital signal such as image or audio data. Such information is embedded in a way difficult to be removed in order to easily identify relevant information for many different purposes, such as the copyright ownership of the media, source tracking, piracy deterrence, etc. There is an extensive literature about watermarking algorithms and methods as well as possible attack techniques. In this work we collect a part of this vast literature in order to make easier for a non-expert reader about watermarking to have a high-level overview on new trends and technologies related to multimedia watermark algorithms and attacks.