If you set up your device to spin up a new IPv6 address every hour (or even every minute), how will they track you using IPs?
On macOS it's 24h, but it doesn't have to be:
$ sysctl -a | grep temppltime
net.inet6.ip6.temppltime: 86400Minutes or less I guess would defeat tracking, but then what's the point?, it's almost equivalent to NAT it still breaks reverse connectivity? and does it actually work?
It also feels like a workaround for an oversight.
But how would they know it is to the same node?
I have my DSL router-modem reboot every night, and I get all sorts of crazy results for ads: I'm in southern Ontario, as is my ISP, but they service folks in Quebec, and so sometimes I get Youtube ads in French since (per my IP) I'm "in" Quebec.
Similarly with the reboot I get a new /64 prefix delegation (actually /56), so I would hazard to guess if IPv6 starts getting tracked, I'd get the same crazy results.
No one cares about tracking by port. Folks are tracking by IP(v4) address.
I know this first hand because I have my DSL router-modem auto-reboot every night (built-in Asus functionality), and I get all sorts of crazy results for ads: I'm in southern Ontario, as is my ISP, but they service folks in Quebec, and so sometimes I get Youtube ads in French since (per my IP) I'm "in" Quebec.
And given that I have IPv6, most OSes generally use that as a first preference for connectivity, and so my IPv6 address/prefix is "in" Quebec.
And this is even with cookies enabled, which should make tracking by browsing easier (esp. since I get decently-accurate recommendations based on viewing history), but yet I still get French ads because my IPv4/IPv6 address is "in" Quebec.
So I have no idea what people are talking about when they say IPv6 will make tracking easier than IPv4. With RFC 4941 it's a solved problem IMHO and no worse under dual-stack than it is under single-stack.
With IPv6 chances are your ISP has a single large address block, and then they split out parts of that address space to users in ontario and quebec. Unless the ISP publishes details of where they've allocated those blocks, any external site is just guessing.
With legacy IP chances are they have multiple small fragmented blocks, some of which are routed to ontario and some of which are routed to quebec so they're a bit easier to keep track of unless the ISP decides to move them.
Also when you address changes, the legacy address space is probably quite close to full so your previous address is released and probably taken by another customer fairly quickly. The IPv6 space will be much larger, and so recycling occurs far more slowly.
Either way youtube is just guessing, it only knows that the address space belongs to a canadian isp and it has to use the behaviour of whoever used those addresses last. If the previous user set their browser language to french and searched for french sites, youtube will remember that and is more likely to serve you french ads.