http://www.iykpqm7jiradoeezzkhj7c4b33g4hbgfwelht2evxxeicbpjy44c7ead.onion/deeplinks/2018/02/how-congresss-extension-section-702-may-expand-nsas-warrantless-surveillance
In both upstream and downstream surveillance, the intelligence community collects and searches communications it believes are related to “selectors.” Selectors are search terms that apply to a target, like an email address, phone number, or other identifier.