I've never understood why companies feel the need to combine personal data with browsing history. If I want to sell funnel cakes, I don't need (or want) to know

I've never understood why companies feel the need to combine personal data with browsing history. If I want to sell funnel cakes, I don't need (or want) to know the personal details of everyone at the carnival, I just need to setup my funnel cake booth AT the carnival.