Is money earned from the internet haram, and is it permissible to spy on subscribers to know the websites they visit?

Internet service is a medium that can be used for both permissible (mubah) and forbidden (haram) purposes. There are three scenarios for selling it: First, if it is highly probable that the subscriber will use it for forbidden purposes (such as pornographic websites), then it is not permissible to sell it. Second, if it is highly probable that the subscriber will use it for permissible purposes, then there is no harm in selling it. Third, if neither of these is known, the default is permissibility, unless depravity is widespread among subscribers; in that case, selling it is forbidden unless it is possible to block forbidden websites. It is not permissible to track the websites visited by subscribers unless they are informed of this, in order to preserve privacy and avoid spying, based on the Almighty's saying: "And do not spy."