I don't particularly want to be tracked and generally block as much as it pratically possible (browser plugins, piholes etc.), but I occasionally encounter usef

I don't particularly want to be tracked and generally block as much as it pratically possible (browser plugins, piholes etc.), but I occasionally encounter useful ads (for example an interesting temporary exhibition I wouldn't have known about, the reprinting of a book that I had been looking for or a better offer for some service that I'm already paying for).