The great internet dishes your a personalized world, that is just designed to your order. This is not something specific to internet.

The physical world around you is also sculpted by your actions. You "feel at home" while at home only because you have adjusted it to become your mould. You become an integral piece in your world, making you a piece in jigsaw puzzle which won't be complete without you.

Your bookshelf, for example, is moulded around your interests. Your wine cellar has your favorite wines. Your clothes just fit your fashion. That's your world. When you visit internet, it presents your own world. It reflects an awareness about you, just like your wardrobe does.

In wardrobe case, you intentionally made your choices. In the internet case, you intentionally expressed your interest by your implicit interactions that were enough to be translated into your selections.

Nothing spooky.