For my reference:
In simple parlance, upstream collection means the NSA accesses the high capacity fiber optic cables that carry Internet traffic and copies all the data flowing through those cables.
The agency is then supposed to filter out any “wholly domestic” communications that are between Americans located in the U.S.
Data collected “incidentally” on U.S. Citizens is generally not destroyed. It is minimized. As we will see later, this became a problem.
Intelligence Agencies can then search the data using “To”, “From” or “About” queries on a target of Section 702 collection.
“About” queries are particularly worrisome.
They occur when the target is neither the sender nor the recipient of the collected communication – but the target’s selector, such as an email address, is being passed between two other communicants.
For more information see FISA Surveillance – Title I & III and Section 702.
“About” queries were abruptly halted by NSA Director Mike Rogers on October 20, 2016. This was formally announced by the NSA on April 28, 2017.
The events leading to this decision are described in this post.
This brings us to a table from the Inspector General’s Report.
Table 3 (page 7) shows four types of violations. The most frequent violation – 5.2% of the total – came from Section 702 upstream “About” queries.”
