I'm trying to outline the capability differences between ArcServer and Portal and can't seem to find any documentation. Can anyone point me in the right direction?
ArcGIS for Server allows you publish your data as services to be consumed in web maps and applications. Portal for ArcGIS allows you to create web maps/applications that are hosted on your infrastructure. Portal for ArcGIS is very similar to ArcGIS Online, the main difference is that it located on your own hardware rather than in the cloud.