The NMRA (National Model Railroading Association) supports various SIGs. SIG stands for "Special Interest Group". These groups have a more-narrowly-defined scope of topics that they cover, catering to those who also enjoy those same topics. NMRA members can join any number of SIGs, and it is part of the set of benefits that NMRA membership offers.
In 2012, a group of S-scale modelers got together (virtually) and decided to form the "S Scale SIG". The idea was to provide a means, within the NMRA, to make modelers in other scales aware of S-scale's benefits, and the fact that there are a large number of us modeling in S. This SIG focused solely on the "scale" side of S, hoping to appeal to HO- and N-scale modelers.
By 2022, most of the leadership of the S Scale SIG had either retired or decided to pursue other careers and so personal life prevented their continued attention to the affairs of the SIG. They had a reasonably active online forum on their web site, which was closed in 2021. They sought others to take over the roles, but not enough interest was found, and so the S Scale SIG basically went dormant.
Learning about that, NASG webmaster, Peter Vanvliet, approached the S Scale SIG's leadership to see if they would be OK with having the custom content of their web site preserved on the NASG web site. There was a reasonable amount of overlap between the two sites (e.g. the list of S manufacturers), but the SIG's web site also had some very interesting custom content, and it would be a shame to lose that. The S Scale SIG's leadership unanimously voted to approve that idea, and Peter Vanvliet was given one year to complete the migration. The content was moved over during July 2023.