Plasmonic electromagnetic wave absorbers based on metal-dielectric-metal nanostructures can achieve single and multi-band absorption. Their multiplex absorption spectra depend on the pattern and dimensions of the nanostructures rather than the materials they are made of. In this progress report, an overview of this field was provided, first summarizing the absorption mechanism from the perspective of materials and the nanostructure, and subsequently discussing a selection of examples focusing on their extreme performance flexibility. The already developed and potential applications, including selective thermal radiator, biosensor, and photoelectric detector were introduced. Finally, we explore the expectations in this rapidly developing field and the future challenges, including dynamic tunability and energy conversion.