As of 1 April 2026, the PSJD database will become an archive and will no longer accept new data. Current publications from Polish scientific journals are available through the Library of Science: https://bibliotekanauki.pl
Dynamics of a number of new users registering for the first time to a Polish internet-base social network http://Grono.net is investigated via various regression models. Trends are estimated and the statistical significance of their forecasting is tested.