I have a feeling a lot of HN devs overvalue the value of old data... probably because they have adblockers and dont know what ads they are targeted for. Youtube's algorithm seems to forget my interests after a year (or less), I often have totally new feeds than I did 6 months ago. When I got back into music production and also watched some airplane crash videos my entire feed became music + "dark stories" related content bringing non-stop music gear + engineering related education sites. Almost all ads I see on my phone via Google properties are related to the current thing I care about.
Beyond biographic details which are 99% disconnected from my old individual instagram/fb data (FB can just buy some correlation between email/phone/IP from my credit card or private postage company or whatever) they probably only profile IRL off the last 1-2yrs of your browsing behaviour in most cases.
The classic privacy invading ads usecase is a woman who is pregnant suddenly getting ads for kid stuff before other people they know they are pregnant. They probably won't be getting those ads a year later. At most they are now labelled as potential mother in some macro profile, but for day-to-day targetting it's all about the current thing she's looking at online.
I'm not defending this stuff and macro details matter for privacy at the nation-state and higher level, but my general point is that it's a living machine, constantly adapting with a short timeframe of data to maximize utility, not one that cares much about what you googled a few yrs ago 99% of the time.
Beyond biographic details which are 99% disconnected from my old individual instagram/fb data (FB can just buy some correlation between email/phone/IP from my credit card or private postage company or whatever) they probably only profile IRL off the last 1-2yrs of your browsing behaviour in most cases.
The classic privacy invading ads usecase is a woman who is pregnant suddenly getting ads for kid stuff before other people they know they are pregnant. They probably won't be getting those ads a year later. At most they are now labelled as potential mother in some macro profile, but for day-to-day targetting it's all about the current thing she's looking at online.
I'm not defending this stuff and macro details matter for privacy at the nation-state and higher level, but my general point is that it's a living machine, constantly adapting with a short timeframe of data to maximize utility, not one that cares much about what you googled a few yrs ago 99% of the time.