Local radio stations can advertise local businesses which could be an example of good/useful targeted ad. The difference is of course the targetting is "passive

Local radio stations can advertise local businesses which could be an example of good/useful targeted ad. The difference is of course the targetting is "passive" and they don't know me, at a downside of being only able to estimate the number of listeners. I'd welcome some passive system like that on the internet but have no idea how it could work.