Despite the considerable amount of attention presently devoted to the high accessibility of online pornography, very little formal analyses have been carried out to show how the advent and proliferation of Internet technology has changed the prevalence of pornography use in populations. We conducted an analysis based on objective website traffic data, representing the changes in the number of (1) Internet users generally, and (2) online pornography users specifically, between the years 2004 and 2016 in Poland. We observed a clear increase in the estimated number of people using online pornography in the analyzed period. The observed increase was much faster than, for example, the change indicated in similar analyses based on General Social Survey data. The estimated number of people viewing pornography on the Internet increased over three times (310%) between October 2004 and October 2016 – starting from an estimated 2.76 million in the first period, to 8.54 million in the last. Additionally, pornography viewership on the Internet was almost 2 times more prevalent among male (47%) than female Internet users (27%), and most popular in the 18-27 age group. Importantly, based on our data, a relatively high percentage (25%) of young Internet users aged 7 to 12 accessed online pornography during a distinct monthly period. Interestingly for this single age group, we did not obtain a strong difference in the prevalence of online pornography use between sexes – viewing pornographic websites was as frequent among young girls as young boys. Since our analysis is based on objective data, it does not share the limitations inherent of self-reports. However, our approach also has a few important limitations (e.g. the analysis does not include online activity generated on mobile devices and under the private browsing mode) which may lead to the underestimation of pornography use indices.