How exactly does the Internet router work?

[Born]

Can they see exactly what you have looked up? Or just the site that's been visited?

No I don't look at bad stuff I've just always wondered

[Barkley Hound]

A router allows multiple devices to be used with one internet connection. It can be wired or wireless (wifi). I am not sure what you mean by "they". A router is usually in your house.

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[SBR32277]

A router merely allows a home network to exist and share one internet connection from a cable or dsl modem. As far as seeing what you looked up it depends on the "they" you are referring to. Outsiders see what you looked up based on "cookies" that collect that information. Have you ever searched for something to purchase such as a tv only to notice a bunch of ads begin to show up with tv sales. The cookies inform advertisers of what you are looking to purchase so they can target their ads towards you. As far as "they" being family, your computer keeps an internet history of every site that you visit unless you delete the history or select "incognito" or "private" searches that don't keep a history but cookies will still be used for advertisers.