Abstract
Social networks incorporate an unprecedented amount and variety of textual data. The analysis of this information furthers our understanding of social behaviors and some trends. The study of inherently complex messages sent between users represents new problems for Natural Language Processing (NLP). In this context, the first article in this special issue of the TAL journal introduces the challenges of information overload from social networks, and discusses the use of NLP methods for processing the textual content of these new modes of communication. MOTS-CLÉS : TAL, réseaux sociaux, analyse sémantique.