We analyze the question of intellectual property in computer software, showing that both copyright and patents do not fit to the specificities and needs of this industry. The alternative model of Open Source Software, based on a very new juridical concept called GPL "General Public License", tends to take a growing importance. We explain its main characteristics, which consist to impose to the producers to disclose the source-code of the concerned programs and of any further improvement if they re-distribute/resell it. We show that by doing that it introduces a totally different approach of intellectual property within industrial strategies, based on a weaker intellectual protection. We discuss the consequences of such a movement in instititutional and public policy terms and we enlarge the approach to understand its exemplariness, in the context of a knowledge based economy, for a growing number of industrial activities.