An evolution of the older Business Data Catalog (BDC), BCS provided read/write access to external data sources (like SQL databases or SAP systems) directly inside SharePoint lists.
While newer versions like SharePoint Online and SharePoint 2019 have since introduced cloud-first features and modern communication sites, SharePoint 2010 remains a landmark release. It transformed the product from a basic document repository into a robust, all-encompassing business platform that paved the way for the modern digital workplace. microsoft sharepoint server 2010