It feels ironic to post this on a site which itself does not support IPv6.
$ dig +short ipv6.watch aaaa
2a01:4f8:1c1c:4b9f::
$ curl -6Is https://ipv6.watch/ | head -1
HTTP/1.1 200 OK
To elaborate: I feel that the irony comes from an apparent desire by this website's users towards supporting IPv6, as evidenced by a few articles about the topic on the first page today; Raising awareness of IPv6 support on a site that does not.
Point being, the items on HNs front page are user aggregated content and has naff all to do with HN itself.
Some servers can work reliably with only IPv6, for instance, until you need to contact IPv4-only servers.
I would like my mail server to be IPv6-only, but that's not currently possible, for instance.
I wonder how many customers can realistically hide behind a single IPv4 (CGNAT), given that there are 65535 TCP/UDP ports.
In theory, one IPv4 address can maintain 65535 connections with every HTTPS server (TCP port 443) on the Internet simultaneously. The main cause of port depletion would be when lots of users connect to the same server.
A reasonable number is 1000 users with 64 ports each, but you could probably squeeze in another 10X.
If Facebook started throwing persistent connections left and right, it imagine it could cause a problem, but short of that, it should be fine.