ISPs use a variety of techniques, such as deep packet inspection. Many ISP support centers use commercial software [1] to display a detailed analysis of websit

ISPs use a variety of techniques, such as deep packet inspection. Many ISP support centers use commercial software [1] to display a detailed analysis of website usage whenever a customer calls in for support. This includes the top websites visited, how much data was transferred for each site (yes, including those of a more salacious nature), the number and type of devices inside a home, nearby Wi-Fi networks, etc. [1] This information can then be queried and used used for marketing purposes at the subscriber level (or to individuals within a dwelling). [1] https://www.calix.com/content/calix/en/site-prod/library-html/software-products/compass/net-mgmt/compass-ud/fap/fap-ug/index.htm?toc8066711.htm?80741.htm https://www.calix.com/content/calix/en/site-prod/library-htm... [2] https://www.calix.com/compass/access-analyze.html https://www.calix.com/compass/access-analyze.html [3] https://www.calix.com/compass/consumer-connect-plus.html https://www.calix.com/compass/consumer-connect-plus.html