This paper analyzes Internet diffusion among organizations, based on daily observation of the registration of second level domain names under the ".it" ccTLD. In particular, we analyzed domains registered in the non- profit sector. The penetration rate in the relevant population of potential users is computed at highly separated geographical levels (regions). A concentration analysis was carried out in order to determine whether the geographical distribution of Internet use is less concentrated than population and income distribution, suggesting a diffusive effect. Regression analysis was performed using demographic, social, economic and infrastructure indicators. Finally, we briefly describe further developments in our research. At present we have built a database containing domains registered by foundations, associations, committees and other organizations. The idea was to verify whether a "social digital divide" exists both in terms of geographical distribution ...