Advertisers wish that could be true. Easiest way to know, dear submitter, create a throwaway account in Adsense or Facebook Ads and look for yourself is not a great deal, everything is aggregated. Fellow nerds like to think that you can pick individual people to advertise to, that might happen on Facebook, you can spam with ADs your friends but thats about it.
You are not an individual on the ad systems, you are part of a lot of groups of people based mostly on demographics, locations, and lastly, your browsing habits. You are not seeing ads because someone paid to show the ad to nerd#1, it just happens that nerd#1 in between ages 40 and 50, lives in nerd town, has college education and, yeah its looking for some tool.
Now if you are asking what the AD SERVERS (the system) knows, they know enough to put you in these groups. Now if they share the data or use another provider to correlate their info with someone's else they might have a bigger picture about you.
Oh and it does not matter how much you block scripts of use hostiles and whatnot, unless you are spoffing your device and modem MACs each time you open a new tab, theres ways to track you.
But please, don't let that stop you from doing it, make it hard for them to track you, so more companies can pop up to address your specific way of anti tracking. You might end up on one special list where no Ads are delivered but is instead sold to the ones that like and can take a detailed look on your browsing habits Then and only then your are tracked because you are you. Otherwise you are just a rounding error in some db.
Sorry to burst so many bubbles.