Reference
The technical stuff.
One explanation for every result. IndieIP uses these concepts to explain why a connection is—or is not—good for self-hosting.
Public IPv4
Public IPv4 is an address reachable from the wider Internet. It is the conventional route to inbound self-hosting.
CGNAT
Carrier-grade NAT shares a public IPv4 address between multiple customers. Ordinary inbound IPv4 port forwarding normally will not work.
Static IPv4
A static address stays the same. Useful, but not essential: dynamic public IPv4 plus DDNS can often do the job.
IPv6
IPv6 offers globally routable addressing and can remove the IPv4 NAT bottleneck, but firewalling and ISP implementation still matter.
Prefix delegation
Prefix delegation lets your router receive and manage an IPv6 prefix for your own network.
Own router
Using your own router gives greater control over routing, DNS, firewalling and network segmentation.
Upload
Hosting sends data outward. Upload speed therefore matters enormously, and symmetric service is particularly attractive.
Dynamic DNS
DDNS keeps a hostname pointed at a changing public IP address.
Tunnels and VPNs
Tunnels can work around some connectivity restrictions. IndieIP explains them, but rates the underlying broadband connection rather than the workaround.