This paper presents a theoretical account of legal validity. We begin with a very simple criterial account of validity and discuss the possibility of elimination of such concept by means of procedure described in Ross' paper Tû-Tû. Then we discuss more ambitious theoretical proposals concerning validity, advocated by Grabowski and Sartor. We make an attempt to reconcile and further generalize these accounts. Finally, we focus on the broadest view encompassing the role of institutions with regard to validity. The notion of intermediate anchoring institutions is key in the new social scenarios created through linked-data systems. Some examples are provided.