- I am using alternative search engines, and it seems most do not provide IPv6 connectivity (when they are not wrecked by big tech gigantic network resources, you know "AI"... how to conveniently DDOS alternatives...)
- github.com: zero ipv6 last time I did check. This is microsoft, do not expect anything good, actually expect the worst, for instance they broke recently noscript/basic (x)html for the issues. Can we still create a account with a noscript/basic (x)html browser and self-hosted emails with IP(v6) literals (mailbox@[ipv6:...])?
- steam? games? Did not check lately. I think many CDNs/game servers or good chunks of them are still IPv4 only.
- many email servers: additionnally many blocks self-hosted email servers (often due to the usage of clumsy and inappropriate block lists from spamhaus, a shaddy company from Switzerland and Andore), with a DNS (SPF) or ip literals (even if it is much stronger than SPF).
- A lot of network applications do not leverage the power of IPv6: for instance for the client-server applications (web for instance), a client-server session should be using a randomly generated IPv6 address, if the ISP provides a not to big prefix. Mobile internet IPv6 ISPs seem to provide random IPv6/128 addresses (in their prefixes), but should provide a stable prefix (probably 96bits) in order to let the terminal applications choose "fixed" ipv6 addresses for direct audio/video calls (no central and online name resolution required). A new user-level OS service is required for user application IPv6 address coordination (beware of brain damaged complexity which some vendors and developer will force upon users and app devs for lock-in).