> if your game is an aquarium game, it doesn't mean that your users are only interested in aquarium cleaning products.

Correct.

On the other hand, the topic of the game is just one of the contexts. A trivial example:

At least we can infer that the player likes to play games, so advertising for mobile games, discount gaming consoles etc might be a better match.

yeah but the category "plays games" is too broad, rivaled by "reads blogs". And after the users have seen enough of gaming ads (and not responded) they are offeered the bottom of the barrel: russian brides (true story).

If we are going to go down the road of doing increasingly detailed ad customization as publishers, we will have come full circle to reinventing targeted ads by another name.

> yeah but the category "plays games" is too broad, rivaled by "reads blogs".

Plays x game on y website at z time of the days however should tell you something though.

the question is how it overlaps with what the advertiser wants to promote. e.g. "is looking for new jeans"

It doesn't overlap with everything a random advertiser might want to promote.

But based on the site, game and other indicators it might be a good place to place an ad for:

- stupid mobile games (assuming the audience is just bored)

- discount consoles/games (assuming audience is playing it because they don't have access to a console)

- toys (assuming audience is kids)

- etc

Targeted ads have always been around. Everyone targets their ads. Decide whether to put your ad in the Times or the Sun.

Its the unsolicited tracking/stalking of individuals across communication networks GDPR forbids.