Some technologies that might technically be considered spyware if users have not been told that they are being tracked are in use by legitimate businesses; they include beacons that check if a user loaded a particular web page, and tracking cookies installed by websites or apps. (inc.com)
Brand mentions and co-citations are also very important to Google, in determining the quality and usefulness of a particular web page. (entrepreneur.com)
and co-citations are also very important to Google, in determining the quality and usefulness of a particular web page. (neilpatel.com)