If you go to this page and then click the link in the left-hand margin that says, “Ads on the web,” you’ll see how old Google thinks you are, based on the websites you’ve viewed that have their advertising network’s tracking bugs embedded on them.
Weirdly, Google thinks I’m 25-34 when I visit from my laptop, and it thinks I’m 55-64 when I visit from my iPad, missing my actual age (46) on either side. I am guessing this is because the actual cookie they place (and track) is different on each device, regardless of the fact that I’m logged into the same Google account in both cases. I also am guessing that the way I use my iPad — I read longer pieces, often deep political essays and or literary analysis, which I pick up from longreads.org or Flipboard — is what’s making them think I’m older when I use it.
They correctly identify me as a male on both. I wonder if they know I’m gay? I’ll bet they do. I’m sure there’s a lot of information they’ve inferred about me based on my browsing habits which they don’t show on this page. I’d be interested in seeing it.