This paper presents an overview on the state of the art of semantics for abstractargumentation, covering both some of the most influential literature proposalsand some general issues concerning semantics definition and evaluation. As tothe former point, the paper reviews Dung's original notions ofcomplete, grounded, preferred, and stable semantics, as well as subsequentlyproposed notions like semi-stable, ideal, stage, and CF2 semantics, consideringboth the extension-based and the labelling-based approaches with respect totheir definitions. As to the latter point, the paper presents an extensive setof general properties for semantics evaluation and analyzes the notions ofargument justification and skepticism. The final part of the paper is focused onthe discussion of some relationships between semantics properties anddomain-specific requirements.