Towards understanding the XYZ states - lessons from their lineshapes

In the last decade a large number of states were observed in the quarkonium mass range above the lowest open flavor threshold with properties that do not at all fit to the until then very successfulquark model. Theoretical explanations for those so called XYZ states can be put into two classes:
compact states like tetraquarks, hybrids or hadroquarkonia or extended states also known as hadronic molecules.
In this talk it will be discussed to what extend the mentioned molecular structures can be identified from observables and in particular from their line shapes.