Evolution of ICT in organizations are following two contradictory trends. On the one hand, definition and concepts defining these technologies are loosing specificity, oil the other hand, these technologies take a growing place in organizational life. Characterization of ICT is particularly difficult as ICT are especially flexible and can be substituted easily to one another. The reasons are numerous : supply structure, organizational uses, applications structuring mixing technical devices, organization design, set of procedures and implementation process rules. The argument of the paper analyzes the nature and difficulties of ICT characterization. It develops, then, some organizational consequences, concerning, in particular, implementation and equipment decision.